I know ppl tie a snell when they've got a weight on line because when the weight hits the hook it drives up into mouth, but without a weight does it matter at all meaning in the weightless wacky set up or when no weight is going to touch hook is a regular uni knot just as good as snell?

Not sure, I've always used the clinch knot my whole life for fishing. I don't use weights or football heads etc either, the wacky rig with a 5" senko with a hook already has a decent weight on it I think. But you should always experiment if you're thinking about it already, see if it increases your landing ratio.

A snell knot is used for hooks with an eye that is bent (not inline with the shank).  It's purpose is to put a straight pull on the hook inline with the shank.

 

3 hours ago, Rich12 said:

A snell knot is used for hooks with an eye that is bent (not inline with the shank).  It's purpose is to put a straight pull on the hook inline with the shank.

 

I also will use a snell knot (uni-version) for my flipping hooks, which has the eye in line with the hook shank, for the same principal of driving the hook in the roof of the fish's mouth when i set the hook.

To answer the OP's question: I wouldn't since it seems unnecessary to me.  I use the same Trilene knot for nearly every application, so I wouldn't want to get bogged down with too many specified knots.  I don't think it'll change any hook-up percentages for wacky rigging either.

Interesting thought.

 

Want to try it out and let us know?

I don't think it's a bad idea to snell any up-eye hook.

Yes

run the line thru the front of the eye first. It does give you some leverage and you find you hook them in the upper mouth more. Straight shank hooks work better but they need to be long shank.