Very beginning pilot here (again).....and I am confused about the
appropriate way of holding the stick during the ground roll prior to
take off.

In Thomas Knauff's Glider Basics, he states (p.59, 2005 edition):
"....before signaling to proceed with the launch, the glider pilot
should set the elevator by holding the control stick at the
approximate position that will result in the proper angle of attack.
To do this, move the control stick the full allowable travel fore and
aft, and then find the mid-point, or neutral position. Move the
control stick back about 1/2 inch from this neutral position. This
will be very close to the optimum position for takeoff. Aircraft
designers build aircraft this way."

However, in Russell Holtz's Flight Training for Gliders, I see (p. 27,
2008 edition): "If the glider norally rests on its main wheel and tail
wheel, the stick should be held forward of neutral, so the as the
glider picks up speed, the tail wheel will rise off the ground."

I'm training in a Blanik L-23, which has a main wheel and a
tailwheel. Knauff makes no mention of whether to hold the stick
forward or aft depending on if the glider has a tail wheel or a nose
wheel, yet Holtz does.

(It's been three weeks since I've flown, and I can't remember what my
instructors did.)

For a glider with a tail wheel, which is correct?

--Michael