I haven't design a topwater bait yet. But have fish with them for a very long time, Barrybait is absolutely right, IMO. If you get the weight right and the nose of the bait up in the air just a little the bait pushes the water as you work the bait. However a Popper, Jitter Bug etc. is a different story. I have a large minnow bait that someone made for me that runs shallow (a tiger color scheme), but does a great job on the top if I just move it along without cranking, because of the way he weighted the bait. BIG FUN, in fast rocky water with Smallies.
Make a few with weights in different locations near the rear and find what works for you.
Dale