Just got the "main" package in. Full TI 64ohm, 19-21, and PK shells.
I threw the 19-21s in some Yincrow X6 shells (I killed a driver by opening and thinking, "Oh, did a hair fall in, better pull that out... *yank* that was a driver coil...") with cheapy RY cables. The shell is properly drilled out in the cable stem area, black horseshoe foam on the shell, bare driver. Only additional thing I did was cut a notch at top of the shell where the driver would fit to avoid any issues.
Impression of 19-21: Bright, mid-forward and a bit lean on the bass (in this config). Compared to the X6s, like night and day. I was missing a touch of upper-mids and especially highs on the X6 for rock and acoustic stuff; the 19-21s deliver that. More intimate sounding with a strong center image, not as spacious in soundstage but I prefer that with brighter tunings. Bass is still there, but not as much punch and some roll-off into sub-bass. It kicks for songs that kick, but doesn't when not called for. I did full-foams with these otherwise the highs get a bit hot. Overall, exciting and has a great balance for non-bass-heavy music, great companion to the X6s. Power-side: Low sensitivity kind of makes me push them more.
Quick edit: As
@Rary pointed out below, I put shrink tubing on the cable through the shell stem--would block much of the air. Forgot to mention that due to me being used to headphones. It's not a super tight fit, but still filling quite a lot of gap. That's why I'm getting a brighter sig, but the bass still delivers enough to satify. I'll try taking the tubing off later down the road, but still enjoying the sound they produce right now for the music I intend to use them for.
On my next order I'll get some tuning cotton and foam, so I'll try some stuff.
@Drcynwa17, I'd add these to your list. Cheap and good for your genres. Not Jazz, but Marvin Gaye sounded good on these.
https://www.aliexpress.com/item/4000281063945.html