.73mm Dunlop Flow for guitar, 3mm Dunlop stubby for bass.
I like the attack of the Ultex material for guitar (pretty sure that’s what Flow is made of), but I find Tortex is easier for me to play with. For bass it works, since it smooths out the attack to my ears compared to Tortex (which I used to use). I suppose I could just use Tortex for my lead playing more, but I’m trying to “desensitize” myself to Ultex.
I’ve grown to dislike nylon for guitar. It doesn’t wear the way I like, and I can feel the roughness when I play harder lines. It doesn’t bother me at all on bass.
Thin picks with a point also have the attack I like for guitar (Ultex keeps them from being floppy), but if I just wanted more speed / control, I would switch to my 1.5mm Jazz Tortex that’s worn in, or maybe even the “traditional” non-pointed Ultex (but keep this one thin, since rounded + thick feels sluggish to me).
I experiment all the time. I find that if my technique is feeling off, changing picks feels like a “refresh” on the session. If I want something totally different, I’ll play reverse grip Shawn Lane style and use an Ultex Jazz (but come to think of it, I should try out my 1.5mm Tortex Jazz). Only consideration is to keep the picks separate, since reverse grip wears them in the opposite direction.
Also, I generally have a rotation of the same model pick on my desk with different wear amounts. There’s a noticeable difference in feel when playing harder lines with a pick that is worn in (smoother), versus a brand new one (can feel a bit jarring).