What size whacky worm hook would you recommend for a 5 to 6 in. stick bait? 1/0 or perhaps 2/0? I have not fished whacky style but would to start. Also, what stick baits do you prefer?

I have gone to the VMC NEKO hook and and reach for 1/0, but have not seen  a decernable diffpin the 2/0,  I do use 2 "0" rings crossed to keep the hook perpendicular open areas.

Nothing is better than a Senko, and you'll (almost) never lose fish with a 1/0 Gammy Octopus Circle Hook, which works well with 4-6 inch Senkos.

If you don’t plan to use with o-ring at least 1/0 is the way to go. With o-ring I can go as small as #2 for less snag. I’m also a fan of VMC Neko hook, got 1/0, #1 and #2 both weedless and regular.

I'm using the Mustad offset neko wacky o-rings, with Berkley or Gamakatsu #1 or 1/0 weedless wide gap hooks.  When using the o-rings, I find the smaller hook sizes work best.

It depends on the style/brand of the hook.  #1-#1/0 VMC nekos will work for 5"-6" stick baits.

I use #1 with an o-ring set up. Owner or Trokar.

I like a 1/0 gamagatsu octopus hook with a gyc senko as well. 

I like the #1 owner.  Sometime instead of a senko try a trick worm , it works great.