when i call down with crap i have a very specific read on the players bet sizing or of the situation; obviously im very exploitable if im constantly calling down a player who splashes around a lot when i have any sort of showdown value

i think here it is fine to bet/fold as you suggested, and its also fine to check/raise the first bet...but once there is a bet and call in front of you, its muck em say uhh time even though your pot odds have improved...reverse implied odds will now be a big factor

as played id have certainly check/called the turn rather than led