If you crank the thread down harder on the first few wraps, you can splay the bucktail out more, making a deeper body without adding more material. Sparse doesn't necessarily mean slim-bodied.This should add to their translucency.
The Ray's Fly imitates silversides and sand eels. What good is it, if it becomes something it is not meant to be? It is the ultimate thin silhouette fly. In fact there are times when one cannot make it thin enough. It can be at its best after many bass and all there is left is one herl, torn body braid and no more than 20 pieces of bucktail left and it keeps on ticking. That's a fly.
True, its great at imitating thin bait, but if the same scheme also works on deeper-bodied prey with a simple modification, why not? Versatility, grasshoppah, is the key to successful flyfishing!