Hold off on the flogging for now you are correct there is allot of USD conversion info out there but like you said not much specific info, and if there is specific info it doesn't necessarily work with your application.
I'm no genius but I'm a very intelligent idiot, so I will give you some of my experiences with my USD conversion.
I started with forks and triples off a 03 CR125R then used a set of conversion bearings from All Balls Racing, (there conversion bearing finder seems to be broken right now I sent them a email yesterday to see whats up with it)
Using the All Balls conversion bearings made it a painless job.
But I soon found out that the 125 forks were severely under sprung (even with the 125 springs having the same rate springs as my stock forks) and stiffer springs are unavailable.
I have since switched to 02 CRF450R forks with springs and valved for a 200 lb rider,
what a big difference the bike handles much better defiantly worth the $.
So in short make sure that heaver springs are available for what ever forks you get, and I suggest going with twin chamber forks (some CR250s came with them)