I am rewiring an old house (50s) with romex to have the flexibilitiy to run it outside conduits when necessary and to further protect the wire from creatures plus making it easier to upgrade in the future (not breaking drywall, etc). So, on the subject of emt conduit inside walls, I would imagine that given that the romex is not requried to be in conduits whilst inside walls then the fact that the romex is not inside a conduit all the way would then acceptable. The situation is depicted below:
In this particular situation the electrical box is inside the concrete exterior wall since there is a cavity in the concrete wall for the box only (and no indentation in the walls for any wire), so I can not connect the emt conduit to the box (yep, I reamed the conduit and also using bushings whenever the wires exit the conduit). Also, I don't want to drill larger holes in the joists (at least not with the exterior walls) for the conduit, so the conduit does not go all the way to the attic; and once in the attic the wire should travel in conduits unless very impractical. Given that the wire is not travelling 100% of the time inside inside the conduits I assume that derating of the conduit is not necessary and that I can fill the conduit even to 100%. Also, I would rather not drill larger holes on the joist for the conduit. I just want to double check and make sure that this is acceptable?