Ok, carbs are back together - see
this post for the results of my adventure with an ebay ultrasonic cleaner (spoiler: it was a rousing success).
New gaskets & o-rings, left the needle clip at 3rd from top (manual says 4th but I'm clearly not running stock), replaced the needle jets (at least one of the old ones looked a bit ovaled by comparison to the new ones) and the JIS screws for cap screws.
Tomorrow I'm going to do some more reading to figure out the best way to measure the float heights, and where to set the idle mixture screws (I've got them on 2.5 turns out which is the Dynojet stage 2 recommendation, as I suspect it has at the very least a dynojet main in it). I'll also see about doing a bit of a bench sync to get a baseline before syncing & adjusting idle when they're back on.
Before they go back on I still need to check the valve adjustment - checking looks to be simple enough, and I'm hoping they're within spec so that I don't need to order shims! (I'm itching to get the bike running - but I'll do what it needs, so if it needs shims, then I'll wait until I have shims).