It should say somewhere on the frame what size it is – backside of the seatube near the BB.
The “ting” thing with the X-Fusion is a bit of a “they all do that sir”. We’ve got 2 in the house – one on my other half’s Flare, the other a 50mm drop one on my Fugio. There’s a loose shaft, not dissimilar in dimensions to a chunky spoke, that is part of the activation mechanism and can rattle. Sometimes mine does, sometimes it doesn’t. Not noticeable when riding.
I’m a couple of cm taller than you on a med. Rocketmax – but a bit short in the leg for my height. There’s a basic issue with “standover”. and that’s that with a 29″ wheel, an appropriate length fork, and a headtube long enough to weld the TT and DT to – the front end of the TT is always going to be quite high, no matter how short the seattube is. It’s never been a practical problem when out riding – in fact I can’t even recall standover being really a fucntional issue ever since I was riding a 21″ Raleigh Amazon…