Ok, this is just an idea. Don't take this as a recommendation. But for the guys that just cannot handle the DA pull, this could be something you want to know.
You CAN remove the decocking feature on the P-64 by modifying the disconnector. There are spare parts on gunbroker, regularly. Disconnectors are typically $15.00 -$20.00 or so. Some guy has 50 of them for sale right now @ 15.00.
http://www.gunbroker.com/Auction/ViewItem.aspx?Item=233391103
If you're mechanically inclined, you'll figure it out in just a few seconds. The angled forward bottom edge of the disconnector is what pushes the sear free during decocking. If you take off the right grip panel, you can see where this edge interacts with a triangular shaped nub sticking off the bottom end of the sear. If you grind out that edge of the disconnector, the gun will no longer decock. You could also grind off that nub on the sear, but sears are much less common and usually cost more.
The gun can then be carried cocked and locked. But you must make sure the sear is fully engaged when the safety comes off. If you don't remove enough material, you could create a dangerous situation where the gun partially decocks.
The gun is fairly easy to decock manually if you take your time, if you want DA for any reason. I decock manually by:
1. point in a safe direction
2. block firing pin with thumb
3. pull trigger
4. release trigger to engage halfcock notch
5. turn on manual safety to engage hammer block and firing pin block
6. lower hammer while continuing to point in a safe direction.
The main benefit of doing this is that the gun is not drop safe unless the manual safety is on. When the pistol is dropped on the hammer, the halfcock notch can fail and the gun can AD. Also the gun may fire if dropped muzzle down. The manual safety physically blocks both the firing pin and the hammer.
So the guys that think they can just carry it around with the safety off and cock it for SA fire, they might want to think again. You should really keep the manual safety on anytime a round is chambered. So you'd have to remove the manual safety and then cock the hammer in order to fire the first shot in SA. Same goes for DA carry. Yeah, it's a heavy first pull, but you should still leave the safety on.
I have read two reports of the gun AD'ing when dropped with hammer down and safety off. Both were posted on the "unofficial P64 forum." In both cases, the gun was dropped indoors, so we're not talking about a hard hit on concrete. In both cases the gun fired upwards, not muzzle down. The first account was a year ago. The owner dropped the gun while putting it back in his safe. He was shot in the arm. The second account was a month ago, or so. The gun fired through the ceiling, just inches from the owner's head.