Have personally had good luck w/ the reaction little dipper w/ a 3/0 owner cps. Like the green pumpkin watermelon if I'm around bluegill or one of the shad variants otherwise....also excellent on a 2/0 core tackle tush if you are using it on an a-rig. Funny thing is if I'm throwing an underspin it's usually a 5/0 owner flashy swimmer w/ the skinny dipper which is the big brother of this one and that's my favorite underspin...I actually don't throw smaller underspins much...tried it but usually if I'm throwing the smaller bait it's in a pond w/ a lot of grass and I just prefer the 3/0 cps twistlock since I can put a mid size rage bug or a 3.5" dolive stick on the same setup and basically have 3 different lures on one rod that all do well depending on what sort of mood they happen to be in that day.

Old school Swarming Hornet now Fish Head underspin works good in 1/8 oz with 2 1/2” to 3” swimmer of choice, including pin tails for both Bass & Crappie.

Tom

I've caught a lot of bass (largemouth and smallmouth) on a 3/16th oz ballhead jig and a 4" Keitech Swing Impact (non-fat, longer skinny ones).  I like Keitech and Owner jigs.  Just cast, let it sink to your desired depth, and slowly retrieve.  As a HS Coach this is what I always have my newbies use.  I used this to finish 2nd in a tournament earlier this year when the wind was blowing 30 mi/hr.  

So many great jigheads out there, but with the popularity of FFS buying them is like highway robbery.  An excelent head that isnt 2x over priced is the berkey half head.  Witha stupid sharp #1 hook its good for smaller profile baits like 3" Easy shiners/SIs, hazedongs and the like.

I use a horsehead jig, think Roadrunner, when I want a small underspin for my smaller paddletails. The hooks are normally thin wire, so a reel-set is all that's needed. Anything over 1/4oz. I'm upsizing the bait/