When I try to weather fabric I use a a stiff wire brush and a razor balde. I first rub the blade across the fabric on the flat of the blade (as if I was giving it a shave) this will gently sever the serface threads at a very controled rate. then I go in with the wire brush and brush away, this further fatigs the fabric. The prosses is repeated untill the desired affect is achived. If you want to create a larger hole you might start buy cutting a hole, smaller than you need, and scrapping and brushing it to the size and shape you want. Be wary of the fluffy effect this can create on some sinthetic fabrics, unless you are going for that special bunny tail look.
Try it on some scraps of cloth see what you think.