MIDI Pitch Bend +100% reaches one octave higher, and -100% one octave lower.
That means a semiton pitch bend is 8.3333…% and it can not correctly be controlled, but it is also hardly to recognisable.
So we can use the following values:
+12: 100.0%
+11: 92.0%
+10: 83.0%
+9: 75.0%
+8: 67.0%
+7: 58.0%
+6: 50.0%
+5: 42.0%
+4: 33.0%
+3: 25.0%
+2: 17.0%
+1: 8.0%
0: 0.0%
-1: -8.0%
-2: -17.0%
-3: -25.0%
-4: -33.0%
-5: -42.0%
-6: -50.0%
-7: -58.0%
-8: -67.0%
-9: -75.0%
-10: -83.0%
-11: -92.0%
-12: -100.0%
I hope the range would not be changed in any future version of Dorico.