Did you read the link to my thread? Cutting the plexi is easy if you already have a CP cut. You can just trace your CP.
Lew,
Did you include the link in your post above?
Mr. Clean,
If you want the plexi to match exactly, and didn't create your CP with a CNC machine, you are going to want to follow Lew's suggestion that he didn't link to above, and use your CP as a template for a flush-trim bit.
You can rent a router at Home Depot, if you don't want to out with the money for your own.
An added bonus is that you can cut all your T-molding slots at the same time.
If you are planning to use T-molding, you will need to rent a router anyway.
The danger of having an plexi overlay that doesn't quite match is that you can pinch your buttons.
I've got a friend that bought a cab that the plexi didn't quite match on, and there were two or three buttons that would hang up if you tightened the pal nuts all the way.
That would cause the button to squeeze itself just tight enough to hang up when pressed.
He ended up having to use a file on those holes to get them to match the CP better.