Merle, I have the no plate pan on mine, it fit great side to side, but I also had to cut down the opening. Yea there are gonna be gaps, and I am still trying to figure out how to "mask" them. But the thing I learned from being around the body business is , fiberglass doesn't fit. So modify it! I prefer to function more than look good. Besides people other than B-body nuts won't even notice. Mines been on for about a year + unpainted or primed and all I get is compliments about how the car looks cool now.
If you do solve the gap issue please tell us. As far as the rubbing... my side gate opens fine after grinding, the tail gate still rubs, but I didn't want to grind anymore away. I don't "use" my car much anyway.