Let me adjust the units of the width of the stroke function

I use vectornator for creating stained glass patterns, I really like the app and use it a lot.

One problem I got with the app, I can only set the size of the stroke by x.xx points. I would like to adjust the units to millimeters.

While make a stained glass pattern I want to make the stroke exactly 1.4mm, this is the exact width of the channel of my lead came.
When printing the created pattern I can cut out the pattern and know if I cut out the stroke which is exactly 1.4mm my glass wil perfectly fit the pattern