Aimstraight, there are a few ways to keep the backstrap permanently compressed. I find that most of them are an overdone job, and the easiest way which also can be quickly reversed if required is to use Sugru. Get access to the bottom of the grip safety lever by removing the right grip and the bottom part of the backstrap which slides out after you remove the bottom pin.Roll a small ball of black Sugru and insert it under the bottom of the grip safety.Now compress the safefy fully closed with your hand and allow the Sugru to set overnight. The rubber will hold the the lever shut and the transfer bar will be permanently be in position between the hammer and the exhaust valve. You can remove the rubber easily at any time if you want the grip safety to function.

Baz