Again, thanks very much for all of the input guys. This is indeed more trying than building an AR, but I expected it to be and wanted the challenge.
Ok, so I've manipulated the right tang on the sear spring and it holds the grip safety out nicely now. I'm actually able to cock the hammer (it does indeed stop at the first notch), and will lock back in full cocked position. A pull of the trigger fires the pistol as it should. But there are still a couple of things that need tweaking.
I had the pistol fully assembled, and racking the slide back cocks the pistol, but the slide only goes back barely enough to cock the hammer and does not go its full travel. Obviously this is an issue, it seems to have a hard stop, at first I thought it was catching on the ejector, but it isn't. I can't quite determine what is stopping the slide from travelling.
The other issue is, when I cock the pistol, the hammer comes back so far that it pushes down on the grip safety and depresses it.
The good news is, the pistol cocks fully, the trigger fires the pistol, and the thumb safety stops the pistol from firing. I've just got to get the action working correctly, and get the hammer to not push the grip safety down.
I'm not getting frustrated, and I'm certainly not going to rush anything, I want this thing functioning completely safely before I test it with snap caps.
Then I might mail it off to Tom so his crazy ass can do the first live fire! >:D