Happy to provide what help I can. You may also want to check on the Glock forum. (www.glocktalk.com) since you are loading for a G20. Used to have one but only have the G29 and G40 now. (Plus a 1911).
When loading for bullets I can’t locate data on, I look around at multiple sources for similar bullets. Then start low and work up as usual.
MOST of the time, I believe the only issue you will find is terminal performance between bullets designed for the 40 vs 10mm. Bullets primarily designed to work well at 40 cal velocity may over expand or fragment at 10mm velocities and have insufficient penetration. (If you are worried about terminal performance)
As always YMMV but I’ve not run into an issue with bullets between the 40 and 10mm and I shoot a LOT of pulls and blems.