The packages of worms I've seen aren't clear on which ones float their rear ends up for best action. Are Mann's jelly worms the best for this? Robo worms?

Strike King makes a finesse worm from the elaztech material, floats great.

Deep Creek Lures soft plastics all float. 

Strike King makes a finesse worm from the elaztech material, floats great.

I think they are  3 X worm , you can pull them and they are like a rubber band, And they have a garlic sent. Best floating worm that I have seen!

Zoom trick worm!

The Strike King 3X Elaztech Finesse worms float better than any worm I have used. They can be a pain to rig though. Like CWB said, heat up the cork screw keeper on a screwlock jig and the job will be easier.

Zoom trick worm!

Trick Worms don't float.

The Zoom trick worms don't float but they do stand up real good on a shakey head.

The Strike King Elaztechs do very good also.

What about the squirrel tail? The tail on those is supposed to float real well.

i've had good luck with;

trick worm

and late last year Hags Tornado

I'm kind of partial to the Berkley Power Shaky Worm, but I really hate the Power Bait stench.

Deep Creek Lures soft plastics all float.

And they smell great! The 6" MT Floating Worm in watermelon is one of my favorites for the shaky head.

Gambler giggy stick.

no better action than that for what you are asking.

There are a lot of videos on You Tube that show the action of different baits which are pretty informative.   You can tell if the tails of worms float for example. 

A problem with them is that the people working the baits in the videos don't have much of a clue.  For instance they'll "jig" a shaky head rig up/down with big hops very fast, not how it is supposed to be fished.

I wouldn 't worry much about which worm flots best, I 've been sakey heading for 3 decades, caught tons of fish and none of the worms/creatures I fish with "floats".

PowerBait Hand poured finesse worm, Zoom Mag Finesse, Roboworm float tail up.

Trick worms floats tail up too! You gotta nip that bulb at the end of the tail off. Floats tail up like a Roboworm. *disclaimer* at least my pack does.

StrikeZone Lures Shake Up Worm. Hands down best floater out there. Not many people seem to know about them....this is a good thing.

The Dizzy Diamond by Bizz Baits floats like you cant believe they are new company. also if you contact them they will do custom orders as well and make the worms in super soft plastic!

Is the elaztech a third-party patented formula or something only Strike King uses?

Gambler Giggy Stick is good

In my experience, the two most buoyant plastic worms

are the Gambler Big Stick and Strike King 3x Finesse worm.

Strike King 3x plastic (AKA: ElazTech & Cyberflexxx) is inherently buoyant,

whereas the Gambler Big Stick has a hollow body.

For fishing in heavy vegetation (e.g. central Florida), I prefer the Gambler Big Stick,

which has a head of tough plastic. On the other hand, 3x plastic is jelly-soft,

and a T-rigged worm frequently gets impaled in heavy cover.

Roger

Try the Kicker Fish Hightail worms. the tails stand up great.

check out this link:

https://www.kickerfishbait.com/hightail_movie.html

Zoom trick worm!

trick worms don't float

What about the squirrel tail? The tail on those is supposed to float real well.

They do.  They're a pretty solid choice.

Another one for the squirrel tail