I don't think I would go any thicker. Stainless is a poor conductor of heat, and if you're using wood for fuel then a few extra sticks won't really matter, but propane is another story. A lot of commercial pans are 22 gage.
I see an appeal for multiple, smaller pans vs one larger pan for those times when you're only boiling a small amount....no need to accumulate "x" amount of sap before lighting the fire. And, if you have enough sap to use all three, then you can simply add the contents of one pan to another as it reduces. This would allow a safe level of sap, and keep you boiling on less propane. How many trees are you planning on tapping? Also, consider a 6" height on the pans unless you keep a very small boil.
I would leave the broken tap alone. The tree will heal around it. Re-tapping the same hole will likely lead to greatly reduced sap yield. The tree closes off the wound internally, so even opening up the old hole will not be as good as a fresh tap, moved 6" or so horizontally.
