When I throw a weightless wacky presentation using one of those Reins 4 legged cross worms, I rarely feel a bite even when I have dropped the thing directly off the side of my kayak with very little line out. What I almost always see is the line start to move and straighten out. If I don't see the line move and a bass gets on, I end up having to dig the hook out of their tummies.
For top water frogs? Just keep an eye on your lure. When a bass comes up for it, you'll almost always see it, hear it. I don't think line watching would help as much as in other presentations. I'd throw straight braid, no leader.