I'm just an amateur, but I'll throw in a few thoughts/ideas regarding the bathtub shot. First, there's a right-left imbalance on the OOF areas. That distracts my eye from the subject. Second, clods of dirt don't make good bokeh; it might have worked better when the field was sprouts 6-12 inches high. Third, this might be a job that needs maximum DOF on capture, then add blur in PS afterwards. Fourth, maybe not use blur at all, but capture at full DOF and slightly desaturate the dirt.
You might be able to rescue the shot by adding blur to the dirt in post, but balance it left-right. Again, I'm an amateur, so take this FWIW.
One more thing: it's a really interesting concept -- if you can make the execution work it could be a very compelling image.