I have a deep pan on my 98 4R70W, it took right at 18 quarts to fill the system(drained completely prior).
From what I saw, all of the aftermarket pans add about 2-3 quarts, none more than that. I liked mine at $200, they've gone up about $25 I think, came in bare AL, or black PC, or polished for a lot more.
None of them will hang too low, and they are made for the 4WD filter, so they aren't a bunch deeper.