I'm having a oven built and need some info about vac line set up as the builder has shown concern about heat transfer and gauge damage ect with the set up i planned to use. As the inside of the oven is made from galvanised steel and the bulkhead fitting (and some other bits ect) are steel will mounting them direct through the outside to inside give heat transfer problems ??. The builder thinks the whole vac set up will get to hot. Will the use of a Sython as in the pics be of any use ??.