As I said when we were chatting, it's good. But again, if it's a Fed ship, perhaps it might need not be a Starfleet vessel because of the general design lineages of the TMP-era (as you said this ship was in) Starships used by Starfleet. Though I wouldn't count out usages of unusual ship designs by Starfleet, it seems more plausable as a civilian-ran Federation medical ship given the design, and maybe cover the ship up with lighter paint along with the medical emblems and maybe markings for an NAR registry?
Just some ideas, that's all. Still, it's a nice ship and I think the polygon count (562) is quite nice.