I have not read all the links on tow hooks for towplanes.......

Most STC's are paperwork.
What works is "sorta based on normal tow position" from what I see.

The issue here is.....when does "out of position by a fair amount create an issue for either end!"....

Forget high tow vs. low tow.....separate discussion (hammered many times on RAS....)....

Some is design, some is maintenance, some is how you fly a certain tow type.....

An inverted Schweitzer hook may be fine, if maintained.....same as a Tost or others....
A towed ship waaaayyyyy out of position may FUBAR ANY hook system.....