When I watch streamers playing midstakes I sometimes hear them contemplate whether to check back or c-bet a certain flush draw holding when they are the PFR (the same holds for delayed c-bets when a flush draw is picked up on the turn). Also in the From the Ground Up course here on RIO, it is once mentioned briefly that we cannot bet all of our flush draws but rather need to split them up over our betting and checking ranges.

This brings me to the question which flush draws should be checked back as the PFR? I have some ideas, but no idea which one to follow up:

1. We could check back nut flushdraws that provide us with SDV when it's checked through even when we don't hit. So this would mean to just check back all Ace high FDs and to bet the rest.
2. We could base our decision on the blocking potential of our holding. For instance, on Jh9h2s a hand like Kh3h would be a good candidate to c-bet since we block substantial parts of the PFC's calling range (KJ, KT, KT etc.). Similarly, a hand like 6h4h would be a worse candidate to c-bet since we unblock the PFC's calling range. But since we are just never good with 6 high on showdown, aren't we more incentivized to bet exactly these low kind of hands???
3. We could simply use a RNG and e.g. decide to c-bet 80% of the time when we hold a FD and check back when we roll low, independently of the hand that we hold.

Which way to go?