I went with this one for my ScubaSteve / Kal hybrid ripoff setup. It's a monster. If my math is right, I'm going to need to have the top of the element no more than 4.5" off the bottom to still be able to do an occasional 5 gallon batch. I went with the 102q instead of the 82q because the diameter is actually 1/2" less.
I'm going weldless on the element and dip tube, but having a bung welded on for a temp probe. I just didn't want to deal with aluminum.
I thought that with a dip tube I can get pretty darn close to the bottom of the pot without resorting to a bottom drain, but I may be wrong, as I've never used one before.
Keep me updated on what you find, as I'm in the same boat as you.