Although replacement nylon fittings are available, the all-brass T-fitting that Sunbeam Specialties supplies is a far superior set-up. I’ve installed a few of these and like them over anything that might fade with time (white nylon, rubber hose, etc.). Plenty of heat up there and not much cool air between the carbs.
Installation is simple. I have found it easiest to loosen BOTH carbs and manuever all the parts into place- offers you sufficient room. You should not have to readjust the carbs, as you’re not messing with the throttle or choke cables or the interconnecting linkage. While you’re in there, I would examine the rubber diaphragms in the suction chambers, and check the dashpot oil level.
Sounds like an easy afternoon project – good luck!