Hi David, great question. Yes, you can display measurements to individual sides of the rectangle when using the guide. The trick is to set the measurements on the guide first, then draw around it.
Drawing with any guide is just like drawing with the line guide — the app totals up the distance you drew from the point of setting stylus to the screen to lifting the stylus off again, hence calculating the perimeter of the guide. So when you select a rectangle you’ve drawn, you’re really only selecting the ink and its associated perimeter measurement. Yes, you can change this to a custom perimeter, but as you’ve found, it isn’t very helpful!
The measurement tags on the guide are what you really want to work with, not the inked line. To draw with the guide using particular measurements, use these steps:
- In the Precision menu, set Measure to active.
- Activate the rectangle guide. You’ll see the measurements appear along the sides.
- Tap+hold a measurement tag and enter in the value you’d like. The guide will adjust the length of that side to what you specified.
- Do the same for the other measurement.
- If you’d like to keep those measurements in place, tap each tag to stick it to the screen.
- Draw around the guide.

Hope that helps, if you have any more questions, please let me know. Good luck with your plans!
Kind regards,
Erica