Just thinking out loud.
Once UTG folds and we are heads up with button, who i presume is a tight/good player and we decided we would try to bluff him if a 4th flush came on the river would raising the turn be better?

Then you can bet/fold on the river if the 4th flush came, bet/call if your non heart straight hit and check/fold everything else and fold if he 3 bets the turn.