I'm having difficulty organizing my thoughts on this subject.

Game is HU and rake per hand is 10bb/100.
Room policy is "no flop, no drop."

Because you only pay rake when seeing a flop, it is preferable to open 3 big blinds.

However, you face either of these opponents:

1) Player A, against a 3x, defends 40% of his big blinds.
2) Player B 3bets 50%.

Both players give you incentive to decrease your opening size. However, if you start minraising with a wide range and either player adapts, all players are now probably playing a -EV game. It can take a long time before your stats suggest your opponent adjusted. By the time you realize it, the rake potentially kills any positive win rate you may have had.

So what's the solution? Should you take advantage of an opponent's perceived leak and risk playing a -EV game by minraising? Should you stick with the original plan of 3x-or-folding and exploit in other ways?
I have my own hypothesis but I'll wait before influencing.