JOB COMPLETE! Finished up Saturday, re-routing the Lav sink to the shower grey tank. Easy job but the basement is 17" high and the heat duct made it "interesting" when it came time to maneuver in there. Backed filled the new tank with well water using my Flush King to check for any leaks in the drain piping. It passed! One thing I noticed is that this new tank has more ribs on the bottom than the original one. It does not sag nearly as much with liquid in it. Anyway, here are a few more photos.
New sink pipe to grey tank:
Looking from the road side access door the capped (old) pipe can be seen as well as the toilet pipe with flex coupling:
Quickie Flush installed. Much easier to do before installing the tank (obviously not the usual option)
Quickie Flush water connection. Used #8 x 1/2" stainless steel sheet metal screws to fasten: