since they make tacks and brads in many sizes, i would attampt to use the original holes. if the tack doesn't hold i would increase one (diameter) size until it does. supplementing with an adhesive, or double face tape, would help keeping the cloth in place while working.
the only (ole' timer) trick i know to help avoid splitting is to place the point of the nail opposite the grain direction. in other words, when viewing a nail from the sharp end, the bevels are usually in a diamond shape. place the longest points perpindicular to grain direction so the nail "cuts" the grain on the way in. i have seen this work. but many nails do not have the diamond shape, in which case i just make sure some points a re perpindicular to the grain.