Ok well I did some calculations and it appears that I have a 12" sub in a bass reflex enclosure tuned to 55hx (?!?!). I have about 15.cu.ft. to play with too, so that's decent for HT use.
The Mids are 5" so it'll take some work to get the right ones there.
As for the x-overs, I think I'm going to just see how the original CV one's work out, thus saving that as a last project (unless I get really lucky).