the biggest issue will be the floor mounting bolt pattern and the hose
connection locations - these 2 can take a lot of time and work. If
it's that old - maybe the floor under has problems and needs to be
redone or at least properly refinished, maybe the hoses have problems
and need to be replaced, ... A friend replaced to Raritan PH heads
with 2 new PHII heads - he was assured by Raritan that the floor bolt
patterns were identical - well - almost - but that 1/2" is a big deal
when the bolts are glassed in from the back and there's no access
except by sawing it all up.

Far easier and cheaper to repair the existing setup. check the outlet
hose to see there's no buildup on the inside - if there is - remove
the hose and beat it on dock to get out most and clean rest with acid.
replace the joker valve and try it from there.



Second question: What's the best way to handle the different floor
mounting bolts, or will they be different?

The boat was a liveaboard and the toilet seems to be plumbed correctly,
from what I can tell having read the archives here.

Thanks!

Stephen