This thread reminds me that sometimes the old-school ways are best.
I read a while ago about Dean Martin, when he was playing a lot of golf and almost always had money on the line.
Playing with someone for the first time, he'd ask: "When you're playing really well, what do you shoot"? And then he'd give/take strokes based on that.
Seems smart and sensible to me, i.e. essentially, tell me what your best score will be. Rare the fellow, I think, who could look you in the eye and take your money after bettering by 3 or 4 strokes what he said was his "best score" just a couple of hours earlier.