Another vote for Romans, Its hard to tell if the sink knob is actually plastic when its installed on the MK1, the core of it is metal and the threading is so perfect when its screwed on it's feels completely solid, even if you flick it with your finger it feels and sounds like metal to me.
Halliwax - mrwax is correct, I would prefer to avoid the H or C on the end cap if possible. I want to a build a logo-less 'in universe' version, it is just the aesthetic I prefer. Having said that, the way I intend to display it - standing up - the bottom won't really be visible. I'm looking forward to getting the Romans MK1, there is no doubt it is a fantastic piece of craftsmanship.
I have to ask is the "Wax" ending of your user names coincidental, or are you two related?
It is supposed to fit, but better contact RbReplicas to make sure. I don't know if the threads on the Roman boosters were always the same or there's difference between the runs or maybe between static vs fx version.