everything sounds good, the only advice i will input here is about one of your cutting methods. i do quite a bit of metal work at home and ALOT of metal work at my dayjob, and if you have extensive cutting to do i would like for you to seriously consider the 4 1/2 inch angle grinder that was mentioned earlier. the cut-off tool you got from harbor frieght is nice to have for small jobs but for lots of cutting you will be very frustrated by it. you wont be able to cut very fast(not that is a horrible thing) but unless you have a very large, very powerful air compressor you will be in sorry shape. i have a 80gallon tank with a single cylinder compressor and the cut off tool wears it out. basically i can cut for about one and half-two minutes then i have to wait five minutes for the tank to fill back up. you can buy cut off wheels for a 4 1/2 angle grinder and you can really slice up some metal with it. youll never have to wait for the compressor and your electric bill will thank you for it as well. plus youll need the grinder anyway for shaping and smoothing panels.

just my two cents

good luck with your project