Couple of things, pocketing is NOT the way to go when cutting tenons IMHO.
First off the shoulder all around the tenon should be about the same size. For instance, if you are tenoning 3/4 stock the tenon should be 1/4 thick and the shoulders should all be about 1/4 all the way around.
If you are cutting square tenons (and I do not know why you would do that since you are probably cutting the mortises on your machine too and that means you would have to chop out the corners of the mortise) the procedure I use for both round and square is the same:
Offset the tenon by the amount you want to cut, repeat that offset until you are clear of the outside of the piece. Then use those vectors with an "outside" profile cut. I like to use climb cutting, seems to result in no splintering.
When I am doing a lot of tenons I use a spiral to avoid as many retracts as possible.
One thing to remember is that you can cut quite deep because you are side cutting in end grain. It cuts really nice.
Pocketing works, but I am not crazy about using it for tenons. BTW, I did a project two years ago that required over two hundred mortise and tenons. I got really good with the tenoning jig I built for the front of the machine.
Oh yea, hopefully you are cutting the mortises first? It is easier to fit tenons than the other way around IMHO.
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