If the fitting is 1/2" threads I would just put a washer and oring on the inside and the coupling on the outside. If your planning on putting a valve on it I would use the valve instead of the coupling.
I use a compression fitting as a bulkhead on mine. I have a washer on both the inside and out, a locknut, and only one oring. I have had no leaks and I just connect my ball valve to the compression fitting. I did that for my dip tubes too
Thanks for all the suggestions! I really appreciate it. Life has gotten in the way of experimenting with actually doing anything with the suggestions though. I found a local welder/homebrew guy who might just weld them in for me. I'll keep everyone posted.
Any updates on this? Curious what size pot and what size coil you have there. I'm about to order one of the Stainless Brewing coils for a 62Qt Bayou Classic pot, but unsure as to what diameter to order (don't have the pots yet, so I can only guess at the proper diameter of coil at this stage).
My suggestion is to get the pot, measure it yourself an then order based on that. I got the comprwssion fittings welded to save the space. Not recommended. Definitely go with the pre rolled HERMS coil worth every penny and just about the same price.