Can you shoot the P10C "high thumbs" / thumbs forward? Or does the design place your thumb right on the slide release, holding it down (so you never get slide lock)?

Having shot ambi HKs for years my thumbs forward (thumb pads) don’t touch any part of any gun anymore. I have no issues with the P10C.

The reason I've never bought any modern HK designs.

The P10C slide release levers are really slim compared to the HK. I will try to get someone to help me take a picture of me holding it with my thumbs forward grip when I get to work.

I always shoot my P-10 thumb forward and never have an issue riding the slide release button. In fact there is a textured area on the forward part of the frame to rest your thumb.Very nice feature.