ORIGINAL: Strat2003
I'll second Ram Jet's technique of glueing it in place with CA and using the Great Planes tool to mark the hole centers.
I also like to do the drilling on a drill press, held in my two-axis vice. That keeps the holes vertical.
I left the drill press out because I just bought one in December after wanting one for about 20 years. I will use a drill press also but not everyone has one.
Bill