Q1: 21 1/2. If you ever get into Tuna fishing or have a bumper veggie crop, you'll want the largest size you can get. Pay now or pay later in all of the extra time it takes to run a smaller cooker.

Q2: No difference other than the extra time needed to pack smaller jars. Jar size doesn't matter when cooking, only packing.

Q3: If you want to remain married, always can fish outside on a propane burner.

Q4. Yes. No problem.

Q5: No. Jars are jars.

Last piece of advice. Buy a double burner and two canners. I run a single system, but I really wished I had doubled up. Pressure canning is easy, just make sure you keep the pressure consistent for the prescribed time. Never leave it un-attended. A simple wind shift can easily mess with your pressure, so stay on top of it.
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