the rcmk gaskets are pretty thin, about half of a 4 bolt zen, but it will still decrease the squish a few thou...
personally i'd use gaskets to goo, properly torqued they don't leak, if i do use goo i use just enough for a very thin layer on each surface so i don't get goo squidgeing out the seams, seems like quite a lot in the pictures...it doesn't take much to squidge out to disrupt the airflow thru the transfers
i looks like a chrysler 300 station wagon weighed down at the back with groceries
i'm interested to see it run... and stiffer rear springs should help some