OOP Set faces 3-flush on turn. What is standard?

Not an actual hand, but a typical situation I've run into.

assume .25/50 blinds
also, I'd like thoughts on how to handle this with short-stacks (40-50 BB) and with average stacks (100BB+)

Hero is OOP with pocket pair ( 5[img]/images/graemlins/spade.gif[/img]5[img]/images/graemlins/heart.gif[/img] )
Preflop is reasonable... say:
Hero limps
MP2 raises to 1.50
MP3 calls
Hero calls.

Flop comes ($5ish): 5[img]/images/graemlins/club.gif[/img]8[img]/images/graemlins/club.gif[/img]A[img]/images/graemlins/diamond.gif[/img]
Hero leads for $4-$5
MP2 calls
MP3 folds

Turn: ($15ish): 2[img]/images/graemlins/club.gif[/img]

Hero???

What's my standard line here:

(a) with a 40-50BB short stack.... say I started with $20, and now I'm down to about $13 left

(b) with a average 100BB stack... ???


For (a)... if the other player is aggressive, is it always better to try to attempt a check-raise on the flop? Or should I always be betting this?

Thanks!