Don't be so quick to give up!
There are more fish in the depths than on top.
The size you are using sounds OK, as does the Red rind. But you said you were "dragging" it on the bottom. That's TOO slow. What you want is to OCCASIONALLY touch bottom, and swim just above it. Go lighter if you have to.
Pork rind or squid strip, there is plenty of action in that flutter. Imagine that you are trying to provoke a "reaction" strike. That is where the predator thinks the bait has seen him, and is going to get away. Of course, this is hard to do, because you have no way of knowing when a fish is eyeballing your offering. All you can do is repeat the action again and again until it provokes a strike. Resist the urge to pull too fast however, as it is an unrealistic speed for a bait that size. "Low and slow" and OCCASIONALLY bumping the bottom, but not "dragging" it.
Flounder