I agree with these guys, don't give up on it, you can beat this thing. If you can, rig up an overtravel stop, it will help alot. When I shoot my 48's, I hold them very lightly, and my forehand is only a shelf for the gun to rest on, very light grip with the trigger hand, and just touching my shoulder with the but. A very good way to see and hear what your rifle is doing is to hold the rifle in both hands away from your body so that you're looking at the top of the rifle, only hold the gun and don't brace it against your body at all, just hold it, point it in a safe direction, and pull the trigger. You can observe the trigger by doing the same thing, just point the gun in a safe direction and fire. Every time I get a new gun I do these things, I find it helps teach me about what the gun is doing and how the trigger feels because you can concentrate on the characterisitics of them without having to concentrate on a target aswell.
As for the tourquing, if it doesn't improve after a few tins of pellets I would tune it myself or get someone else to do it. You wouldn't beleive the difference between a Diana 48 that has 3 or 4 thousand shots through it, and one out of the box or farly new that is untuned. HTH,
Mulby