Assume 100BB deep, TAG image. Sorry for the generality of the question but I think it can still be tackled. Let's say I 3bet a tightish reg MP open out of the blind with Q9s and the flop is K59r. Or with A8s and flop is J68r.

Should we treat our MP as value or as having no value? I think that determines our lines. This always confused me. Should we c-bet? Or are we turning our MP into a bluff by cbetting and we can c/c? I understand this depends on V's 3b flatting range - let's assume he happens to flat wide - 55+ and KJo+.