Anybody have and luck with these? Particularly large bass

Yep. 7/0 EWG hook or offset worm hook. Watermelon seed. I've caught dinks and donks. Ideally, bigger bait = bigger fish, but I haven't much noticed a difference. I will say, I like the action of bigger flukes better.

I bought a 5/0 hook for them, hope its big enough

I bought a 5/0 hook for them, hope its big enough

 

I use a 5/0 offset worm on normal flukes. I jump up bigger on magnums b/c the 5/0 doesn't go far enough back to the tail. I feel I lose fish on a short bite.