Hmm, well, finished soaking, chopped mine up, and... it's only one cart-full, but not bad! I cut a strip about 1.5 times the width of the (tiny) 40x inner cart, then halved that into two long strips, stuffed it in and whee. The 'gentle' density took on a noticable dent in the hot water, but seems to have done fine in the cartridge so far.
I'm thinking CVS is not the place to go between the fragrance and the price (finally found the detail buried in the other thread and Walgreens is 2 for less-than-the-price-of-one, though I don't know how the sizes might differ). Also that the 'gentle' may not be the best, even in these little carts - it's almost as soft as the polyfill (maybe 50% stiffer), and has visible big gobs of adhesive in it, as well as one side that's obviously 'the stiffer side.' The 'regular' stuff might bounce back a bit better when using the 'hold it aside with a paperclip and shove a dropper in there' fill technique, and trap a bit less liquid... I couldn't get it 100% bone-dry, but I did get about 100 big drags off it in immediate succession (for science!) before it failed to deliver, with maybe 75% of what-would-remain-trapped-in-polyfill remaining (hard to eyeball; it'd be fun to compare by mass but I don't have any of that equipment around). And no leaks.
So yeah, in 6 months when this is finally used up I think I'll try the kind everyone else has been using. But maybe get another one of these for my face.
(This is also store-brand, just CVS, and teardrop-shaped like some of the dollar-store ones that were photographed, so I have no proof that it's more or less 3M than anything else. But there's the faintest trace of 'peach' coloring to the rougher side that might help identify the style if it turns up elsewhere... I guess the 'regular' is completely white, though it was hard to tell through the box.)
I guess if there's ever some runny liquid that leaks from the 'regular' type, the thinner fibers in the 'gentle' might be some sort of advantage.
Edit: Just found a few more cartridges where the polyfill was starting to get matted, and while the first one I 'puffed' was just a little less dense than polyfill, I tore another 2mm off this strip and 'fluffed' the remainder to more like half-of-original-polyfill-density before wedging it in. This seems like perfection... it's wicking better than the first, even with the thinner Dekang, it's still not sliding out of the cart, and there seems to be more than enough surface tension to prevent spillage in the little 40x cup. I'll be back if I'm wrong and wreck a battery after this gets some 'pocket testing,' but hopefully that's a hint for others - aim to have the open spaces between fibers be around half the width of a droplet, if that makes any sense - at least, the droplet from a 10ml Dekang bottle.
