I just installed a 5 piece tub surround in my shower/bath after a bunch of the old ceramic tiles fell out, and I have a space I need to refinish that the tub surround panels didn't reach. there is about an 8 inch space all around above the plastic panels where tiles were removed and now there is bare drywall. I need to fill in this area somehow to make it even with the panels and seal up the drywall. It doesn't have to look perfect and may not be painted "until I get around to it", but I need something up there. Should I use joint compound (which I understand uses some kind of putty and there is some tape involved somehow), or spackle, maybe some water resistant spackle? quick set compound? something else? this involves something on the order of 500 - 1000 square inches and will need to be as deep as a ceramic tile, water resistance would be nice. thanks in advance for any help!