diff --git a/glyphs/autobuilds.ptl b/glyphs/autobuilds.ptl
index c9fbe61..9dabed6 100644
--- a/glyphs/autobuilds.ptl
+++ b/glyphs/autobuilds.ptl
@@ -3,6 +3,7 @@ $$include '../meta/macros.ptl'
 
 import 'unorm' as unorm
 import [mix linreg clamp fallback suggestGC] from '../support/utils'
+import [designParameters] from '../meta/aesthetics'
 
 define customDecompositions : object
 	# Latvians use comma instead of cedillas in several letters.
diff --git a/glyphs/common-shapes.ptl b/glyphs/common-shapes.ptl
index c6be0c8..f3c0f75 100644
--- a/glyphs/common-shapes.ptl
+++ b/glyphs/common-shapes.ptl
@@ -4,6 +4,7 @@ import '../support/transform' as : Transform && [object [transformPoint tp] [unt
 import '../support/fairify' as fairify
 
 import [mix linreg clamp fallback] from '../support/utils'
+import [designParameters] from '../meta/aesthetics'
 
 export : define [apply] : begin
 	glyph-module-entry
diff --git a/glyphs/letters-unified-basic.ptl b/glyphs/letters-unified-basic.ptl
index de49708..8bb3665 100644
--- a/glyphs/letters-unified-basic.ptl
+++ b/glyphs/letters-unified-basic.ptl
@@ -6,6 +6,7 @@ $$include '../meta/macros.ptl'
 
 import '../support/transform' as : Transform && [object [transformPoint tp] [untransform utp] inverse]
 import [mix linreg clamp fallback] from '../support/utils'
+import [designParameters] from '../meta/aesthetics'
 
 export : define [apply] : begin
 	glyph-module-entry commonShapes overmarks
diff --git a/glyphs/letters-unified-extended.ptl b/glyphs/letters-unified-extended.ptl
index fdba3e4..d998997 100644
--- a/glyphs/letters-unified-extended.ptl
+++ b/glyphs/letters-unified-extended.ptl
@@ -1,6 +1,7 @@
 $$include '../meta/macros.ptl'
 
 import [mix linreg clamp fallback] from '../support/utils'
+import [designParameters] from '../meta/aesthetics'
 
 export : define [apply] : begin
 	glyph-module-entry commonShapes overmarks letterBasic
diff --git a/glyphs/numbers.ptl b/glyphs/numbers.ptl
index 0a7458d..f920f83 100644
--- a/glyphs/numbers.ptl
+++ b/glyphs/numbers.ptl
@@ -1,6 +1,7 @@
 $$include '../meta/macros.ptl'
 
 import [mix linreg clamp fallback] from '../support/utils'
+import [designParameters] from '../meta/aesthetics'
 
 ###### NUMBERS
 export : define [apply] : begin
diff --git a/glyphs/overmarks.ptl b/glyphs/overmarks.ptl
index c4cfc97..6b5fa24 100644
--- a/glyphs/overmarks.ptl
+++ b/glyphs/overmarks.ptl
@@ -1,6 +1,7 @@
 $$include '../meta/macros.ptl'
 
 import [mix linreg clamp fallback] from '../support/utils'
+import [designParameters] from '../meta/aesthetics'
 
 export : define [apply] : begin
 	glyph-module-entry commonShapes
diff --git a/glyphs/symbol-braille.ptl b/glyphs/symbol-braille.ptl
index eb39134..9b785a1 100755
--- a/glyphs/symbol-braille.ptl
+++ b/glyphs/symbol-braille.ptl
@@ -2,6 +2,7 @@
 $$include '../meta/macros.ptl'
 
 import [mix linreg clamp fallback] from '../support/utils'
+import [designParameters] from '../meta/aesthetics'
 
 export : define [apply] : begin
 	glyph-module-entry commonShapes overmarks
diff --git a/glyphs/symbol-geometric.ptl b/glyphs/symbol-geometric.ptl
index 3209d85..808e8ea 100644
--- a/glyphs/symbol-geometric.ptl
+++ b/glyphs/symbol-geometric.ptl
@@ -3,6 +3,7 @@ $$include '../meta/macros.ptl'
 
 import '../support/transform' as : Transform && [object [transformPoint tp] [untransform utp] inverse]
 import [mix linreg clamp fallback] from '../support/utils'
+import [designParameters] from '../meta/aesthetics'
 
 export : define [apply] : begin
 	glyph-module-entry commonShapes overmarks
diff --git a/glyphs/symbol-letter.ptl b/glyphs/symbol-letter.ptl
index e319d93..e06c577 100644
--- a/glyphs/symbol-letter.ptl
+++ b/glyphs/symbol-letter.ptl
@@ -3,6 +3,7 @@
 $$include '../meta/macros.ptl'
 
 import [mix linreg clamp fallback] from '../support/utils'
+import [designParameters] from '../meta/aesthetics'
 
 export : define [apply] : begin
 	glyph-module-entry commonShapes overmarks letterBasic
diff --git a/glyphs/symbol-math.ptl b/glyphs/symbol-math.ptl
index c58866b..856c135 100644
--- a/glyphs/symbol-math.ptl
+++ b/glyphs/symbol-math.ptl
@@ -2,6 +2,7 @@
 $$include '../meta/macros.ptl'
 
 import [mix linreg clamp fallback] from '../support/utils'
+import [designParameters] from '../meta/aesthetics'
 
 export : define [apply] : begin
 	glyph-module-entry commonShapes overmarks letterBasic letterExt
@@ -102,8 +103,8 @@ export : define [apply] : begin
 		include glyphs.plus
 		save 'plusminus' 0xB1
 	turned 'minusplus' 0x2213 'plusminus' MIDDLE parenMid
-	local equalHalfSpace : (parenTop - parenBot) * 0.11
-	
+
+	local equalHalfSpace : (parenTop - parenBot) * designParameters.equal_wideness
 	sketch # equal
 		include : HBar SB RIGHTSB (parenMid + equalHalfSpace) OPERATORSTROKE
 		include : HBar SB RIGHTSB (parenMid - equalHalfSpace) OPERATORSTROKE
diff --git a/glyphs/symbol-other.ptl b/glyphs/symbol-other.ptl
index cafcfe0..7c1cff2 100644
--- a/glyphs/symbol-other.ptl
+++ b/glyphs/symbol-other.ptl
@@ -2,6 +2,7 @@
 $$include '../meta/macros.ptl'
 
 import [mix linreg clamp fallback] from '../support/utils'
+import [designParameters] from '../meta/aesthetics'
 
 export : define [apply] : begin
 	glyph-module-entry commonShapes overmarks geometricSymbols
@@ -322,9 +323,11 @@ export : define [apply] : begin
 		save ('lighyphen.' + subclass)
 	 
 	# =>
-	local dblarrowd : XH * [linreg 18 0.15 126 0.275 STROKE]
-	local sw : Math.min OPERATORSTROKE (dblarrowd * [clamp 0.45 0.75 ((1 - WHITENESS) * 1)])
-	local dblextend [clamp 0 WIDTH (RIGHTSB - (dblarrowd - sw / 2) * arrowheadSlope)]
+	# local dblarrowd : XH * [linreg 18 0.15 126 0.275 STROKE]
+	# local sw : Math.min OPERATORSTROKE (dblarrowd * [clamp 0.45 0.75 ((1 - WHITENESS) * 1)])
+	local sw OPERATORSTROKE
+	local dblarrowd ((parenTop - parenBot) * designParameters.equal_wideness + sw / 2)
+	local dblextend : clamp 0 WIDTH (RIGHTSB - (dblarrowd - sw / 2) * arrowheadSlope)
 	local dblarrowj : clamp 0 WIDTH (SB + (dblarrowd - sw / 2) * arrowheadSlope)
 	foreach [{subclass left right} : items-of [ArrowBarConfig dblextend arrowheadsKern dblarrowj]] : sketch
 		include : HBarTop left right (parenMid + dblarrowd) sw
diff --git a/glyphs/symbol-punctuation.ptl b/glyphs/symbol-punctuation.ptl
index f463ea5..d07924c 100644
--- a/glyphs/symbol-punctuation.ptl
+++ b/glyphs/symbol-punctuation.ptl
@@ -2,6 +2,7 @@
 $$include '../meta/macros.ptl'
 
 import [mix linreg clamp fallback] from '../support/utils'
+import [designParameters] from '../meta/aesthetics'
 
 export : define [apply] : begin
 	glyph-module-entry commonShapes overmarks letterBasic
diff --git a/meta/aesthetics.ptl b/meta/aesthetics.ptl
index df31b9e..8873d78 100644
--- a/meta/aesthetics.ptl
+++ b/meta/aesthetics.ptl
@@ -173,4 +173,7 @@ export : define [setFontMetrics para metrics font] : begin
 
 	set font.OS_2.sxHeight          XH
 	set font.OS_2.sCapHeight        CAP
-	set font.post.italicAngle       (0 - para.slantAngle)
\ No newline at end of file
+	set font.post.italicAngle       (0 - para.slantAngle)
+
+export : define designParameters : object
+	equal_wideness 0.1
\ No newline at end of file