i don't know if it will bolt on but usually base spacer + machining off the head + 'wallering out' the stud holes will make kits work as long as they are pretty close. You can port to make up for it being a little off. another good trick is to machine aluminum 'studs' by threading 1/4" 6061 stock and screwing it into the old stud holes with jb weld, then cutting them off flush, that way you can drill a new hole that is siamesed with the existing stud hole without the bit walking.
i'm sorry i've never owned a QT or anything like that so i have no idea if they are close or not. The hardest part is usually getting the top of the cylinder machined off but it sounds like you wont have any trouble.
if you do go with the athena cylinder let me know and i'll get you one of these heads:
that athena is one of the highest performing 'out of the box' cylinders in all of moped dom.... i wouldn't port it much if you're gonna run it on a single speed though, they are already pretty aggressive.
and yeah mikey, i'm with ya, the stuff you were posting a few years ago with the sim software on your peugeot was awesome... i played with bimotion a few years ago... i think for all out builds, variated and shifty's and stuff it works well but there is so much subtelty in those 'not WOT' running conditions for the milder builds and for daily driveable single speed stuff, that the results that i've gotten from sim software doesn't really capture... also i was a lot dumber about this stuff back then and it was definiitely a GIGO type situation. Someday i'd like to revisit it.