Those don't look like they'd be floppy at all.

I use the Jazz iii picks.
 

I also use Jazz III picks. I don't use a pick with an acoustic.

 
Tortex 1.14 Standards for me! They take a lickin' and keep on pickin'!
 
Bob

craigb

 
My preferred pick delivery method. 

I'll pick her! Definitely!

Bob Oister

 
Tortex 1.14 Standards for me! They take a lickin' and keep on pickin'!
 
Bob

These are my preference for electric guitar, as well.

I have one of these. Really good for lead guitar overtones...
 
https://www.etsy.com/listing/121430155/antique-brass-cymbal-pick-for-acoustic?ref=shop_home_active_17
 
I still use Fender Mediums for everything else, lol.
 
Regards,
Dan
 
 

When playing live, I'll always use a standard shape pick 1mm (.88 in a pinch) or thicker. I'm not picky about the material, but I do prefer plastic over nylon. This is for both electrics and acoustics.
 
Studio... that's different - I experiment to get the tone/attack I am looking for on a particular song. This is particularly important (for me) on acoustic parts - especially if the percussive sound of the pick is going to be part of the sound. This might sound tedious, but I really don't spend much time on it... More often than not I grab the size I want before I start playing... I certainly have it chosen within one pass of the song.

I  use the Dunlop tortex .50mm picks for acoustic guitar. I like thin for acoustic guitar, although at least half the time it winds up in my mouth while I play fingerstyle. I have taken the .50mm and bent the tip a couple of hundred times to weaken it for playing fast mandolin types of things.
My favorite acoustic pick was one I got for free at the Styx concert. They were giving them out. I have no idea what it is though.
 
For electric guitar I use a really hard pick with a pointy end...sorry I don't know what it's called :)

40 to 25 years ago Fender medium.

Then Dunlop 1mm small stubby because I needed speed on single string melody work (think Dick Dale) and because they let me have skin/string contact which allows for a lot of note shaping. Then I discovered that a small pick makes hybrid picking much easier.

Nowadays Dunlop Delrin Jazz shape, the stiffer purple version of the pick.

Though mostly I don't use a pick at all, especially for playing blues/"old style" British R'n'B. Mix of clawhammer-ish mixed with banjo frailing using the back of my nails. I never use a pick when playing slide except on lap steel when it's plastick thumbick plus three steel fingerpicks.

Acoustic guitar = Dunlop thumbpick, usually in open tuning or DADGAD.

On bass standard size Dunlop nylon, 1.2mm thick. Or thumb and first finger slapping.

I just wish manufacturers offered all their picks in white. Even better glow-in-the-dark white. The number of picks I've dropped on dark stages or pub carpets, never to be seen again, is ridiculous.