I've recently acquired a Wilkinson bridge with compensated saddles to replace my six saddle bridge so that i can then install a bigsby. The saddles don't have grooves cut in them. I presume i need to attend to this? What sort of file do i need to buy? I noticed that the overall string spacing width on the bigsby is about 3mm narrower thang what the current tele bridge gives me so again, I'm guessing i need to cut grooves in the saddles to keep the finished string spacing as close as possible to original Hopefully I'm not showing my ignorance here!