My best advice is keep an eye on the bikes for sale, you could find one duped to nuts for 5-6k and then have good parts to sell and a base of parts you need , people do what you do all the time then sell them cheap, just my advise after doing it your way and building multiple customer machines
As long as your cylinders are not past a certain point. If someone is clear with intent to me I can port cylinders to a point and still leave adjustability for a decent 4 mil port
You wanna try something diffrent for trail riding, stock stroke long rod with torque porting , boost porting , high compression, race gas , some timing . Power everywhere. I've rece built a few and they are fun and rev excellent
How cheap and what's the condition, there's a reason it's few and far between you see anything about em on this site , and a reason no builder will recommend it .more food for thought the crank is the heart of your engine , treat your heart good and it will treat you good . The added stroke with short rod put unneeded stress on the piston skirt . Don't say I didn't worn you
If you have a choice go long rod the rod angle is much more desirable and IMO a better build. I've seen short rods shake apart . I've also put a few together that are still zingin three yrs later
Rotors are removable but the mounts should be machined into the rim. Mine are banshee taper and have two diffrent inner diameter bearings to accept taper , have you measure and compared yhem to stock hubs