For extra heavy stuff like you're describing, I don't think a 201 is what you want to go with, and certainly not a slant-needle machine like a 301. If you absolutely had to do this with a domestic I'd say a Singer 15-91 is a better bet than the 201, as the 201 has a horizontal bobbin (vs. the 15-91's vertical bobbin), and that extra turn the bobbin thread has to make in a 201 may become a liability.
Be aware that about the heaviest thread you can get in a model 15, or any domestic Singer for that matter, is #69. If anyone's successfully used #92 in a 15-91, please let us know, I'd like to hear about it.
Before you buy that industrial you mentioned, find out what that particular model was designed to do. People seem to think "industrial" just means "super strong for thick material" and that's not what it means at all. For example, a lingerie factory will be filled with industrial machines, and none of them would be suited for sewing webbing to Cordura.
I have one machine that I use to make dog leashes and collars. I'm never going through more than four layers of webbing, but it's a Singer 15-90 (not -91) that I converted to handcrank. There's no motor to burn out, and the handcrank is great for the slow, precise stitching required to do a proper Box-X on material that's only one inch wide. I use #16 or #18 needles, depending, and #69 thread top and bottom.