Any recommendations on underspin jigs for 3.3/3.8/4.3 keitechs (or other swimbaits around this size) where 1) the blade turns unimpeded and 2) the size of the jighead isn't a mismatch to the size of the swimbait where they butt together? 

Swarming hornet's fish head spin is one of the best I've found (for me results wise). There are multitudes of others out there.

 

https://www.tacklewarehouse.com/Underspins/catpage-SCXH5.html

 

Probably 75 plus different underspins in that link.

 

Good luck,

Fishingmickey

Eco Pro Thunderspin is probably the best underspin I have found. Super high quality and it has a Trokar hook on it. 

 

The Revenge Underspins are also nice and come available from the factory with either silver or gold blades. So that's nice if you're particular about that. 

 

And like mentioned above, the Sworming Hornet is kind of the industry standard. However, for me, I've found them to corrode easier than other brands if you leave a bait on the jig. Maybe it's just me, but that has been my experience. I will say, the first tournament that I ever won I was throwing a Sworming Hornet with a 3.3" Keitech. 

Owner Flashy Swimmer ?

 

 

I have been using the 6th Sense Divine underspin lately and really like them.

14 minutes ago, Catt said:

Owner Flashy Swimmer ?

 

 

X2! 

2 hours ago, Dorado said:

X2! 

X3

1 hour ago, Ksam1234 said:

X3

Aaannndddd x4