So, the smoker's done, and here are some pics. The propane tank sat for a while, but once it was cut, it just took a few weeks to finish.
I wound up using nitrogen to purge the propane tank when I cut it, and it was a nothing burger. No sparks, no nuclear explosions, no nothing. I did flip the tank upside down, and vented it from the bottom, so the nitrogen could push the heavier air out the bottom. The safety issue was well worth the cost of the nitrogen tank rental.
This is the sled, tank, and firebox prior to welding.
Smoke stack added, and doors trimmed and hinges installed. I really wanted to build this whole smoker in house, so I wound up cutting the spring handles off, and made my own. I did buy 3 horse shoes though. 2 for the lid supports, and one for the vent cap lid.
I put top racks on both sides, and added hangers for chicken or pork belly.
Bob, ribs are in the freezer waiting their turn. Today, I'm playing with the diffuser plates, and treating the grates with tallow. The side of the tank closest to the firebox was 30 degrees hotter than the stack side, which is normal. I adjusted the plates, and now the firebox side is only 10 degrees warmer.
Getting the heat to level out is a project and you probably never will get it completely equal, I built a whole hog rotisserie and trust me, I had to do a ton of test runs, trial and error before I got it reasonably close, which actually works decent for me because I put the ham end of the hog closest to the firebox end and therefore it works out pretty good, because the thicker meat takes a little more heat or longer time to cook. I will have to post a picture of the way I built my lid to cam over and makes it pretty slick to open.
All the really good ideas I've ever had came to me while I was milking a cow.
Someone mentioned good gloves! Thanks god! People have no idea that good gloves are a saver! Don't forget about other equipment to secure your body and surfaces, such as glasses, special work outfit etc. If you don't have enough experience with that, you can use the suggestions on byuing platforms. For examples, when I purchase my equipment on https://www.cherokeeobserver.org/best-steel-for-knives/, they will always show me "this tool goes well with:...". Sometimes I get really cool instruments like that.