Hi Adam
I've already fitted the machined gears, bought a few upgrade bits on the initial build as thought i may as well get them in their first time. Built the box as you mention to, gear spins fine (within reason with the bearings still having a little grease in them) and is shimmed only to allow enough float to spin (and thats barely half a mm i think). The gear coming in is also spaced right clamping the bearings tight, but not throttling them so there is no float, but free play. I ended up actually building the box with the diff in and no input shaft, and then input shaft no diff to check all this, then again with everything in as well.
I've also put some heatshrink around the CV's but will organise getting some boots for those soon.
Will write back after tonight though...hopefully not in tears hehehe