Should we adjust our bet size based on the number of people in the hand. For instance, we are 5 handed to the flop and the flop is draw heavy. A pot sized bet would offer correct drawing odds for most draws to the 4th and 5th players to act after our bet if everyone calls. So, should we assume everyone will call and over bet the pot based on that assumption, or do you adjust it down a bit assuming some will fold?

I'm not a fan of just pushing the flop in most situations. There are of course times when a push is correct. But for this example let's assume everyone is deep stacked.

Thoughts/ideas/opinions?

Yes you adjust, but not by very much. A small overbet of the pot might weed out an extra player, but big overbets are just spew.

It largely depends on what you're bet is atempting to do - are you building the pot, trying to control the pot size or protecting your hand? A "for Example" would be a lot easier to comment on than such a general concept as presented. Post flop bets have to take a lot into consideration including pre-flop action, position, the flop and your hand as well as the flop and the opps possible hands, your stack, their stack, and a half dozen or more other things. In general thou, overbetting the pot has little if any extra effect than just betting the 75%-100% of pot and may become a tell to obsevant players.
With 4 of 5 limpers to act on a draw heavy board after the 1st in, the pot gets richer and richer as more and more call the 1st bet (and are more and more correct to do so) so unless theres is a raise there's a good chance 3-4/5 will see the turn with a huge pot. If you're on a draw with 8 or 9 out a check-call might be wiser than a bet but with 14-16 outs to a str8/flush draw a pot building raise of 1/3-1/2 pot size would usually pay off big time half the time - but as always -'it depends'..