The only critical dimension on teardrop rack is the alignment of the holes from leg to leg - don't make a mistake and cut them at the bottom. And make sure the crossties are intact in the uprights. Oh, and take the time to drill and bolt them to the floor properly.
I needed some a couple years ago - saw a few pieces sitting behind the local Ace hardware store and asked them if I could buy it. I knew they'd been sitting in the same spot for a long time.
When we looked they realized the base had rusted out on a couple of them, and that's why they were sitting outside. I said I'd still take them, and he sold them for me for $25. That's 3 12foot uprights and 12 crossbeams. I nearly froze to death putting them in the back of my pickup, because it was only about 5 degrees outside and I had to chip the snow off of them, but I didn't want to give him a chance to change his mind.
I just welded some 3/16ths plate onto the bottom of the rusty sections up to good metal, and they are solid as a rock.
I got a couple of wire shelf sections with mine and a few sheetmetal 2x4 type crossbeams. I like the wire shelves, but they want like $25 apiece for them used, so I ended up buying 12 foot 2x10's and cutting them into three pieces and they drop right in. I think I probably have 4-5 tons of stuff up in the air on them right now. I could use some more sections.