Whip open the jet cover (the domes held down by thumbscrews on the top cover), take out the jets and have a look! The values will be stamped on the jets (easily removed with a broad, flat screwdriver). There are 3 values on the big jet, and one on the smaller jet for each barrel.
Really need to know the choke sizes - easy enough to loosen the locking bolts on the underside of the carb body, slide out the aux vents (which also have a useful value stamped on them) and then the chokes which you can have a better look at or attempt to measure with a ruler or something.
If they have 34mm chokes I might just take them...