Thank you all guys for trying to help me.
Unfortunately I've already removed as much as possible but I only managed to reduce the "plus" of tiller from 3/4 to 1/2".
I know that my lack of experience is to blame and that I cannot do anything to make this bow be a hunting one.
I only try to understand what mistakes I made, in order to avoid them in the future.
So, what I've learnt is that I have to cut the arrow shelf 1" above my thumb for a deep grip and that the positive tiller has to be 4 to 6 milimeters.
One more question! Is there any difference between 1 3/4" and 2" width? I know the second is wider
but I mean ... is there any advantage in using one or another?