Make sure your gaps are a little wider than you want. I ( and OSG, Gumptattoo) all used 1.5 chopped mat and thin epoxy resin from U.S. Composites. That is where we got the foam to as it is all compatible. I would suggest cutting your pieces ahead of time, do your corners first and have at least an inch or more wrap around. It is difficult to get the mat to wet out and lay nice around a corner. Then do your flats. I wish I would have known that as I found out the hard way. I did 3 layers of mat. I got all this from the DIY threads from Tcenzi and DMC. Oh, and get yourself a fiberglass roller, helps get the air out.
I agree exactly with what Dsmoke said. Your doing great and I am glad to see more guys are starting to do this. I like the way you did yours for sure. I didn't a flip at the end and the out side of my bags curve in instead of having a corner at the back. What a pain in the ass that turned out to be with glass. Get some dura glass or tiger hair to help any trouble spots before body work. I found that the glass was very strong after three layers and mine only have two layers on the inside and is just as strong because it has the foam as a backer. Are you gonna do the three layers of glass on the fender then carve the foam off of the inside? How thick is the foam on the fender?