On Tuesday, May 19, 2020 at 1:14:22 PM UTC-4, wrote:
I’d suggest we get input from tow pilots who’ve actually experienced an upset. I suspect tow rope angle is not likely to help, but tow plane pitch change and elevator position are likely inputs that can be measured and provide reasonable value. But it’s just a guess. Asking someone who’s been there makes a lot of sense.

Increased towrope angle and increase in tension precede pitch change. Measuring and controlling from these inputs would seem to me to be better than controlling off pitch change, which is an output, and elevator position which is a following output.
FWIW
UH