Curious. There are so many options. Also considering the hands, other tasks, who sits where etc.
But, basically (rather disregarding other tasks):
If I have 1s+2s / 1s+3s / 2s+3s
I would immediately show my shortest color*, and expect a captain (or another player with high sub) mark his length in this color. The moment after that marked card is out, next trick in this color == sub out. If played card is not out until the end, you need t look for another color, or hope another player has high sub to beat yours.
(I do assume if you have 1 sub, you don't have to speed your comm. Although it might be *tricky if you have single 8/9 as shortest color - as you need to avoid earlier tricks...)
If I have 4s + one more sub(1/2):
I immediately comm my shortest color, and start first trick in that. The person with 3sub should react, as in case above.
If I am someone else and the person with this task (tasker) commed immediately:
If I have 1sub: I keep it till the end
If I have 2sub: I keep it until the moment the tasker discards his 1s, and see if 4sub/3sub is out in this trick. If not and the tasker is captain, I can take this trick with 2sub.
If I have 1+2 sub:
...and the person with the task is the capt: I get rid of my subs, unless a person with 3 sub discards theirs earlier, then I keep one till the end.
...and the person with the task is not the capt: I get rid of one sub asap, possibly in 4s-taken trick.
If I have 1+2+3sub: ...argh. At least it is clear, get rid of two of them asap
If I have 3s and player with the task is not the captain: I keep it until 4s is to be in the trick.
If I have 1+3s: I try to take 2sub in the color suggested by the tasker. If I know its impossible, I try to show (by comm or taking play) what color is better for it.
If I have 23sub (and tasker is cpt): I try to take 1sub in the color suggested by the tasker. If I know its impossible, I try to show (by comm or taking play) what color is better for it.