Not to be a wet blanket, but you can't sync the carbs until they are on the bike and running. You need a manometer, or in more common bike terms, a set of carb stix/morgan carb tool/etc.
You can get them what looks close on the bench, but they'll be nowhere near in sync on a running engine. the blade position is determined by the running condition of the cylinder it's feeding, not in relation to the other carbs throttle blade.
Here's me doing a work up of my Vmax engined venture:
The manometer is the long white thing with all the tubes on it. It hooks up to the carbs and the vacuum pulls a column of mercury up the calibrated tubes and you adjust the blades until they are all pulling the same vacuum. there's also a 5 gas analyser on that cart, a battery charger, and a laptop. the 5 gas is to get the fuel mixture correct and the laptop is there because I've got a programmable electronic ignition on the bike. But you still need to know what the rpm is in order to properly set the carbs and the bike mounted tach is not sensitive enough. My ignition box displays rpm and voltage on the laptop, but there's also a tach and voltmeter on my cart. You also need to know engine temp, and there's an oil temp probe on the cart as well.
You can get by without that much test equipment, but my minimum would be oil temp, voltage and rpm. With that, you can get close with rpm drops, but not as close as you can with a CO/HC meter.
You'll also need a couple fans to feed the engine cool air or it will overheat before you can get all your adjustments right. Also keep in mind that "plug chops" aren't going to be very revealling as modern fuels burn much cleaner than older fuel blends and the color you will be looking for on a modern plug/fuel is waaaaay down the insulator by the base of the body. It's actually very hard to actually see the plug ring without a lighted magnifier. About all that stil holds true is you can fairly easily see the plug heat range on the electrodes and the base ring on the carb body threads, but they don't really tell you much of anything about the mixture burn. Not with modern fuels it doesn't.
Luckily (for you), you'll have only two to adjust (and one of those will be the master, so you sync one carb to the master carb vac reading) and not the usual metric bank of four. I still remeber doing cbx‘s. 6 carbs, what a nightmare! I used to quietly dissapear when I saw a work order with “cbx 1000” sitting on the front counter. Did a coupke in my time and that was enough for a lifetime! Only thing worse (IMHO) was the 12 cyl carbed Jags. That was beyond a nightmare. Did one, refused to touch another one ever again!
Again, the procedure is in the FSM. Follow it, as there is a specific sequence to adjusting carbs.
You really should invest in some dip or a small ultrasonic. Spray in stuff usually won't touch varnished up carb passages and running wires through the passages just means they are open, not clean to the spec'd diameters. I generally discourage my buddies from doing the "wire thing", as you can often damage the passages, even with something relatively soft like copper. Not only are most internal passages a specific diameter, they also must be smooth or you risk turbulence , which causes another whole new set of problems. You're probably "ok", but certainly not optimal....
