It might not just be trigger control, if you are shooting two handing you could be pushing/pulling/muscling the gun low and left with your support hand while anticipating recoil.
What model Sig 229 are you shooting? Not many of those have beavertail frames, if you don't like the reset you can add the Short Reset Trigger (SRT) and lessen the reset.
As for the Glock and the "raspberry" I can only assume you mean that your hand is getting reddened from recoil or is your hand turning into a fruit? How many cartridges are you firing each range visit that results in the fruit like symptom? If you're shooting a lot trying to work on your trigger control, yeah your hand might get irritated from the beating.
I'd suggest either:
Get a 9mm conversion barrel and magazines for the Glock and shoot some more
Get a .22 caliber conversion for the Glock and shoot more
Get another Sig.
When you go out shooting again, try shooting from a traditional bullseye type stance, one handed focusing on all the fundamentals (Natural point of aim, sight alignment, sight picture, breath control, and trigger squeeze) if you're still pulling low and left, it is a trigger control issue and not a support hand issue.