There is a video on you tube by Jeff Lange, showing how to build hoerner wing tips (Part 3).
It is a visual version of John Evans fine write-up of years ago.
I did like his use of aluminum tape as a guide.
http://www.youtube.com/watch?v=ULhZchv7itoPS: I plan to keep the leftover foam, he discarded, to make my wing root faring.
You can make the hotwire cut, of the first half, in one piece by putting a nail in the foam block at the leading edge cord line. This will help guide the hotwire for the initial cut. This leftover foam can be used to cradle the airfoil better than the wood block he used when you hotwire the second half. (Old Rutan tricks)