Eastwood makes paint for the carburetors, it looks decent but I have never used it.
I have tried all kinds of carb combinations on my 250 and have now settled on two Carter W-1's from the late '40s. I had three Rochester Model H, two Monojets, one Monojet, and have a Quadrajet rebuilt and ready to try.
Its a lot of time and money to set up dual or triple carb systems. I suggest spending the least amount on kits and cores and do it yourself rebuilding. Get them on the truck and running, then decide if you need professional rebuilds. Over the counter rebuilds are a mix of parts the rebuilder has on hand so its questionable what you will get. It may look good and even run, but getting two identical might be tough.
Be sure both carbs are identical, right down to the make, model, and date if possible. There are hundreds of different Model B, internal and external changes were made through the years. Once you have them in hand, verify they have original parts still inside them, jetting, metering rod, and power valves.
Even when you get a set ready to run, I will bet you find they are to big as a set. My Monojet's are sized for the engine cubic engine I had it on, when I added a second one, the air flow was cut in half in each carb. This created a lean condition since the air is what pulls fuel out into the air stream. Mine ran OK and looked really cool, but the fuel milage was horrid. The W-1's are much small carbs. The air flow through each one is high enough to pull fuel into the engine. Even these have problems with a off idle lean condition. If I adjust out the lean spot, fuel milage drops, so I settled for better milage and learned to drive through the lean spot.
You will never know till you try, so keep at it, but don't be shocked if it takes a while to get them sorted out. I have had the W-1s off four or five times now tuning on them. I hate to think how many times I had the three model H's off.
Joe