20Gauge... one tip on storing home canned goods. (and yes, I'm one of those "nuts" who had over 2000 jars, and filled most of them every year. Since the kids are grown and on their own, many of the jars are now in their homes, and I encourage them to fill them and reuse them, but they usually get "sent home" every few months- and exchanged for full ones of whatever food product we had too much of that year... this year, it's going to be green and yellow beans again, I suspect. Last year it was tomato puree...)
Anyway... it's not advisable to stack full/sealed canning jars. Weight on top of the sealed lid can cause problems with the seal, over time. Even if you store them in their original cardboard boxes, they can break down under the weight and cause problems over time.
What I'd suggest is if you are planning on increasing your storage of home-canned foods (and I think that's a GREAT idea... every time there is a recall of a food product, I look at my home-produced equivalent and think, "gee, it's nice to not have to worry about what's in those jars!!"), consider adding shelves in one section, so they are spaced just far enough apart to comfortably hold jars. Or, to let you slide in full cases of jars.
I'll try to get some photos of our set up... I designed and made the plans for our shelf units, and they have proven to work well over the years. My units to hold canning jar cases are made in a modular form... "towers" that hold 1 stack of jars each. They hold either 7 cases of quarts or 11 cases of pints... and it's very easy to simply build another tower or two to accommodate more jars (finding the ROOM to put more in isn't quite as easy, though! LOL!)
I agree on the "second canner" for convenience, and for letting you get a large crop of whatever processed safely and easily. I have an All American 931... which holds two stacks of either pints or quarts. I was tempted to get the even larger one (which holds 3 stacks of pints, IIRC), but at the time, I had an electric stove and there was already major problems with us having to replace the wiring to the burners every year or two, due to heat build up... I figured the bigger canner would make that worse. Now that I have a commercial style propane cooktop, that's not as big of an issue... but I'm canning for 2 (plus gifts) now, not 6 (and half the high school senior class! LOL!)
Anyway, I bought an All American 915 for my second canner, and it was a great choice. Smaller, lighter weight, it only holds one tier of jars (either pints or quarts). I use it often in the winter... I make "planned overs"; it doesn't take much longer to prepare a large kettle full of soup or stew compared to making 3-4 quarts, and it's simple enough to can the extra while I"m cleaning up the kitchen... wake up the next morning to 7 more quarts or pints of soup or stew to stash.
And when things are busy ( like they will be in a couple of weeks when all the beans start ripening!), I can process 25 pints of beans at a time, which really helps speed up the process.
(for extra trays for the canner, or replacement parts, as well as the best prices I've found on All American canners, try
www.redhillgeneralstore.com)
Pints vs quarts... these days, it's almost all pints, for obvious reasons. I still put tomato puree, spaghetti sauce and applesauce in quarts... also grape juice, and when I sometimes make a big batch of chicken broth but don't have time to turn it into soup, I'll can it in quarts. Everything else is pints. I can pulled pork in half pints, as it makes nearly a perfect "lunch size" batch of sandwich filling. Pepperoni is also in half pints, as is all jam and preserves. The only real drawback is that you use twice as many jar lids, which adds up these days! But I stocked up on Tattler lids a few years back, and I'm using them almost exclusively (exceptions are jars I plan on giving for gifts)
I'll see if I can get some pics... believe me, it won't be as pretty and neat as your storage area! LOL... hubby teases me that we need to dig out the other half of the cellar (we have a basement under the new half of the house, but the other half, which survived our house fire in 1980, only has a crawlspace) just for my food preps and canning stuff! And of course, that means there's lots of stuff we can't keep in the machine shed (paints, etc that can't freeze, and good tools we can't afford to get rusty)... about the best we can do is keep it organized and so we have a clear path to walk!
Summerthyme