I think you're rubber mounting your carbs, so the tufnol isn't as important as it would be with standard manifolds. I normally use JB weld on the joint, and with rubber mounts the carbs stay cool, so no worries about evaporation!
Hi Gav & John, many thanks for the replys. With the different variations of carbs used along with rubber mountings as John pointed out, theyre optional. Given the heat here in OZ (46 deg C or 115 F last week for 7 days ) any help keeping cool can only be a good thing. After 38 deg the bike stays in the shed as the pilot ends up looking like a dried up prune!!