Terry, you're so right about motors being different. Here's something to try before drilling.
Grab yourself a chunk of 2 x 4 and a couple of good C-clamps. Put the 2 x 4 on the inside of the transom to protect the gelcoat, and clamp the bracket to the outside. I did that to mine, and was able to hang the motor right on the bracket and check everything for fit. If it needs to be moved after the frist try, outline the bracket feet with a pencil so you remember where you started. When you get it located just right, mark the mounting holes real good before you take it off. You can also clamp your mounting board to the bracket for the first try. That way you can move it up or down before drilling its holes. You want to make sure that the holes for the bracket-to-transom do not end up too close to the motor well bottom glass, or you won't get the nuts and big washers on.
Remember when you drill thru the transom to angle the drill uphill a little. That way the nuts will be square to the transom and less likely to crack the gelcoat when you tighten them down.
The bracket on the TyBoo22 was the remnants of the store bought fancy job, so I just used the plastic board that came with it. Tim on Lynn Marie used some stuff called Trek Deck to make his mounting board, and Mark on 2nd Byte used sheets of marine plywood laminated together for his. Lyle on Scorpio used some high-tech plastic about 2" thick for his, but I think you have to get that stuff from NASA or Boeing or something.