Ok here's my thoughts on the subject, and I have been shooting it.
I shoot it with my Daystate MK4 Target/Panther dropped in to the standard MK4 sporter stock. It's the same rifle and scope combo that usually sits in the Grand Prix stock. I simply unscrew one bolt and swap them over. I would prefer to shoot the Grand Prix (cause I spent a lot of money on it and I'd like to shoot one rifle).
Personally, I like the idea of no peg, and free choice of position. However, I think it would be easier to do the following:
1. Allow the adjustable cheek/butt pads but limit the depth of the stock (standard MK4 for example) so that you can't just use a hamster or deep stock to rest the rifle on the ground/hand, and it forces the shot to be taken off the elbows a bit more.
2. Use a flat disk, say 10 inches across which is fixed on the shooting line by a 6" nail or similar which some part of the body needs to touch.This stops people being able to take the mick as to interpretation of the firing point.
3. No target gloves. Identical left and right hand gloves to be worn (ie a standard set of gloves) if required.
Just my take on it guys.