What you do here is highly dependent on the metagame. How are your opponents? Fit 'r Fold? Is anyone here sticky? Do you have them just a bit scared of you? When you say you're the tightest player at the table, are they worried about you, or have you melted into the background and they don't notice you at all? If you have a good reason to believe they noticed, then prepare to steal it. If not, take the freebie.
OK, you banged it and got four callers. Given the dry nature of the flop, the chance to improve the backdoor, the limpy, tight, weak opposition, I would be inclined to take a chance and fire that barrel. I'd go $50 here. If they're really fit 'r fold, and that weak-passive you'll drop 'em and scoop. No sense in betting higher: if they'll call for $50, they'll call for more. Weak, passive, limpy players aren't thinking about pot odds, and a bet is a bet regardless of how big or small it is. To them, "equity" has something to do with real estate. Their thinking is way, way
way below that of the 2+2 forum-er. If the c-bet gets called, and the turn doesn't help, it need not cost you any more since either they'll check again, and you check behind, or one of the yutzes will reveal he has a hand, and you drop, having lost the minimum.
No sense in being afraid to lead into four limpers who check the flop. These kinds of players aren't likely to do any check-raising, and their checks mean "I ain't got nuttin'; take my money". If they knew what they were doing, they wouldn't be weak-tight, fit 'r fold, limpy players would they?
If anyone gets sticky here, file that away for future reference.