Back a few posts to your earlier question which I completely ignored. The reason for the ligther jig is to allow the tube to "crawl" with the current, even lakes have a slight movement to the water. Craws drift slightly with the current and the lighter weight allows for a drift. Also, the lighter weight means that if you want to reel the tube in which works great as well to trigger that active attack. The lighter weight means play is more feasible . You can use 3/16 or even 1/4 heads as well but with the 3.5-4 in tubes the size matches almost perfectly with the jigs hook. 3.5-1/8, 4-3/16, 4.5-1/4. Just jamb that jig down the back end of the tube and run it to the front. The hook should just barely arch out where the skirt begins.
To back smalljaw67 he's 100% right about smallies to buckets. Buckets hit baits that look "fishy", and typically from within hiding. Samllies tend to "search out" their meals, which is typically more "creature" like in appearance. Eg. Craws, Hellgrammites. I've hit smallies while reeling a tube on a quick retrieve only feet from where I'm standing. if they want the meal they'll earn it.