I have two drain master electric gate valve's with the waste master. It also will not fit through the deck plate. Solution
www.phasefourindustries.com has an eight inch deck plate to replace the standard six inch from the factory.
Log onto the web site, on the left under products click waste master. Scroll down to the 8" deck plate part number 5575 retail price $15.40
I never unhook my hose from the rv. I have always hated unhooking it to rinse, then trying to find somewhere to hang it up and drip dry. And then that (stuff) would still drip out into the compartment. I know that you may think that not disconnecting to rinse sounds nasty. However, the waste master valve on the end of the hose has made this (process) very clean and dry.
Hope this helps. Kevin