Correct way of holding the stick during ground roll?

Then you need to tell your tow pilot to be a little more gentle with
throttle application.
Even with light students in the front seat, smoother application of the tow
throttle can keep the nose from rocketing up while still providing enough
acceleration to provide roll and pitch control.

I used to fly commercial rides in a 2-33 from a 1500 ft grass runway
with 70 ft trees on one end and a barbed wire fence at the other (about
150 MSL, BTW). You always got an "energetic" start and the nose would
*always* pop up whether you liked it or not. We started the take off
roll with the stick full forward. I would *always* brief the passenger
accordingly.

Tony V.
http://home.comcast.net/~verhulst/SOARING