I would like to get some cascade audio deflex pads to use when i seal my doors. I have 5x7/6x8 speakers and i have heard that it is good to get the pad size 2 inches above your speaker size, so it would seem that the 9" pad would be the good choice. THe next one is the 7". Well, my question is, if the pad happens to be too big on some area like if there is something in the way, is it OK to cut the pad to make it fit, or does it need to be whole to work properly.