I'm trying to install sks fenders on my friend's cannondale T800, and I've run into a problem. The rear fender is supposed to fasten to the brake bridge, through a 'horizontal' hole. Being the weird aluminum bike that it is, the cannondale has a type of 'wishbone' stay, and no brake bridge. The hole for fenders is 'horizontal,' on the underside of the wishbone stay. Here are some pictures



My plan is to measure a bunch, then drill through the fender, and install it with spacers. My questions are, has anyone done this? Is it okay to drill through sks fenders? Thanks!