Percentage of time raiser flops a good hand

[Mark1808]

I am trying to figure out the optimal percentage of time I should be bluff raising a flop against an opponent with say a 16% PF raise percentage and 80% continuation bettor. So I am trying to calculate how often someone who raises X% of hands figures to flop top pair or better or a strong draw? I'm thinking I need to take each individual hand in their range and calculate each percentage and then average them. That seems very time consuming! Any general rules of thumb?