The control horns are pretty easy to install. The locations to mount them have been lasered out for you. Make sure you get a good secure fit. Rather than use epoxy, I use CA glue. I put a couple drops of medium in the hole, insert the horn and then wick in thin around the base of the horn. I have built 6 KMs and never had one failure. The servo mounting locations were engineered to accept Blue Bird 306 servos. Anything else you use will require you to trim the holes. This isn't hard, just take your time and shave a small amount of material at a time. Make sure you use the "forward" holes in the tail.

If you have anymore questions about your build, just post them here and I'll gladly help you out.

Cheers