Shawn
These links address the problem-
Much thanks to Jim Burch and his contributuon to soaring.

http://home.att.net/~jdburch/index.htm
http://home.att.net/~jdburch/towhook.htm
http://home.att.net/~jdburch/Form337.htm
http://home.att.net/~jdburch/Towstudy.htm

This applys to the Schweizer hooks:

"On rare occasions it is possible for a glider on aerotow takeoff to
get so high that the tow plane tail is lifted even with full up
elevator by the tow pilot. It is also possible in this situation for
the tow plane release to jam and prevent release by the tow pilot. One
solution to ensure that the tow pilot can release when this happens is
to invert the release hook. To review an article on this subject from
the May 1996 issue of Soaring, select Towhook Article. Select FAA Form
337 for documentation of such a modification to a Pawnee tow plane,
and Towing Analysis for the study upon which the article is based."

In my opinion the TOST hooks by far are the better answer although
initial cost and maintainence costs are a factor.
Good Luck.
Rod