I am getting a new CalSpa 50amp from the main panel Can i run the indoor (all in one cable)6/3 wire w/ground stranded through studs and behind drywall to the Spa disconnect mounted on the house then from there can i run the 4 seperate wires in conduit does this need to be solid or stranded? also will either one of the SPA gfci from homedepot and lowes work Eaton and Midwest. I read some things about some gfci randomly triping due to the design?

call your town's electrical inspector or call an electrician