OK, carbs are off and my arsenal is slowly being delivered and building up:
Litetek seal kit arrived (cheap as chips even with postage and very high quality - much cheaper than even any of the kits on ebay)
Stainless torx head bolts for the float chambers (the hex bolts that someone has installed in the past are just too much of a faff to get a 1/4" drive socket on squarely)
Two cans of holts carb cleaner
One can of Electolube Air Duster (£18, but the best and most powerful air duster I've ever come across - use it at work fairly regularly when repairing computers)
New fuel resistant 5/16" tubing for the diaphragm breathers, although this is a tad tight and so have reordered some 3/8" stuff, but it won't arrive in time for Saturday
JIS screwdriver bits to remove the diaphragm covers and air cutoff valve covers without damaging the screws
I really wish I'd bought the M600 jetted new old stock BDST 38s that were on ebay six months ago. I think they were just under or just over £200 and I could have whacked them on, saved all this hassle and rebuilt the original carbs in my leisure without taking the bike off the road
Oh well, lesson learned!
Stay tuned for pics, updates and hopefully shrieks of joy...