All-in on a flush draw, sufficient folding equity ?

[Legend]

Consider the following theoretic scenario:

You play 10 handed NL on-line. You are in the BB and are dealt
A(h) K(h). There are 3 limpers when the action gets to you and you
decide to raise 7xBB. The first limper calls and the rest fold.

You have no information on the first limper. He has 70BB left after
calling pre-flop and you have him covered.

So the pot has 15BB and the flop comes:

4(h)5(h)6(c)

You decide to bet the pot, 15BB, and your opponent makes a minimum
raise to 30BB.

If you re-raise all-in here and get called, is it reasonable to assume
that on average you will be about 2-1 underdog or perhaps slightly
worse and as a result the profitability of such a move mainly depends
on the folding equity since the pot is laying you 2-1 ?

If so, given that your opponent has 40BB left, is there enough folding
equity to justify moving all-in, or is it better to just call here
and play by the odds from that point ?

Now, if instead of 40BB your opponent had 100BB left, what's your
preferable move - call or all-in ?

I'd love to hear what you think and what your experience
in such situations is.

[soah]

Against 77 you're 50% to win the pot.
Against JJ you're 55% to win the pot.
Against 78 you're 36% to win the pot.
Against 66 you're 25% to win the pot.

Assuming your opponent will not fold, your decision is to risk another 55bb to win 100bb.

So even with no folding equity it's not a terrible move to push. Against an unknown opponent I think you'll end up with a coinflip often enough to make up for the times that you're in worse shape. You don't need much folding equity to make this +EV.