Apparently you got the carbs waiting to upgrade the cylinders then.
I have seen those 34's and 35mm keihins on alot of ported 350 stuff. LRD, JSD, JD, K&T, Patriot Racing, ILR, Hoffman, Duncan, Jet city, Jaws, Redline, Packard, Trinity, RDZ. The only bikes that ran exceptionally well and fast from what I saw were the Redline, K&T, and The packard motors. Those bikes were full on hill shooters though. Two of them ran side pipes even. It seems like a lot of guys bolt them on just cause they think they can. When I modify or build a motor, or setup a bike. I try to get the person to spend the money in the areas where it will make the improvements he wants. I dont really recommend doing stuff cause it is cheap or it will get him by. My cousin does that shit and it always comes back to bite him down the road. You guys own banshees, just buying them is an agreement to open up your pocketbook just for general repairs when you ride. If you decide to do upgrades, it cost money to do it right.
Run the 35's if you want, I dont know what to tell ya. You wont try smaller duals or a single, so you wont ever know how it would have run. From my experience, no ported 350 shy of a drag bike needs a set of duals that big.