Had a conversation with the good folks at Wrangler NW Power Products. He had absolutely no issue with using the frame as a ground even with a winch, he's done so many times with many different vehicle configurations. He did strongly suggest beefing up the ground straps from engine to frame, and body to frame, good advice under any circumstances.

He also said their hammer-style crimper is all they used to use on field calls, and makes quite reliable connections. So its in the mail, part # 38-101.

Thanks for the discussion, guys! Many counselors make for a wise choice. Or confusion. Not in this case.