I use a bayou classic 20 gallon as my boil kettle. Works great and was a fraction of anything else I could find. As for tri clad pots, if you are using an immersion chiller it might slow chilling down a bit!
I think the term 'fender' washer may be more of a canadian thing. what it is , is a washer with an over sized outside diameter and gives better stability due to this size. i have noticed a lot of varience in this dimension from different manufacturers but as long as the O.D. is enough to support...