youTeflon tape is the easy solution.
I have done something similar to your proposed repair using plastic (nylon?) bits from McMaster Carr.
View attachment 454619
It is hard to change the fuel line in the tank later on if need be unless you are willing to split the tank again.
Looking at that cork gasket in the tank reminds me that over on SH in the McCulloch thread someone found some 3/32" square profile o-ring material you can buy from McMaster Carr, add a dab of Three Bond or Honda Bond at the joint and you have a successful gasket replacement.
Mark