Buy a mouse sander at canadian tire or wallmart, use 80 for the whole thing, the little attachment will go the inner horns, but be very carefull not to sand the wood down, serious it will work, take about 4 hours to do. Been dar done dat. The sander is about 35 bucks, do it outside, wear a facemask. as for finishing them, never got that far yet, just know how to sand em, good luck and have fun staring at the guitar for awhile while ya sand er, its not that exciting do it in a couple of days becasue you might screw it up if you loose your consentration.
Laterz!