[Bubbaman]

I just purchased an HK USP45 Tactical and love the gun with my new Osprey45. The only problem that I have is that I am used to shooting a 1911, placing my thumb on top of the safety with my firing grip.

When I do the same thing with the HK, the safety is high enough on the frame that my thumb can't really ride on top of, or below the safety. Does anyone make an aftermarket safety that lowers the placement of the safety?

 

[HAMMERHEAD]

Riding the safety on a USP is not a good idea. It can and will de-cock the gun when it recoils. Happened on my USP 45 and others.
There are no aftermarket safeties that I'm aware of.
I would recommend either changing your habit of riding the safety or swapping out the detent plate and converting the gun to variant 9, safety, no de-cocker.

 

[H&K 4 LIFE]

Not sure if it will solve your problem, but you might want to try a HK45 control lever, which is compatible with the USP 45.

I also agree that V9 is the best way to go for running C&L.