I don't have any fretting supplies, nor do I have the will or courage to build a neck right now.
You don't have a hammer and a piece of scrap wood?
As far as neck angle goes... You need to have all your pieces out in front of you before you start building. Neck angle on a bolt on is built into the body's neck pocket. However, it seems you're building a neckthrough, so that means it'll be built into the neck. Since Kahlers were originally designed to be a direct replacement for Tune-O-Matic bridges, you WILL need a neck angle. Typically, there's a 2* angle, and a 12" radius to properly fit the neck...
HOWEVER, it all depends on how high you plan on having your neck compared to the surface of the body. If your neck is higher, you'll need less angle. If your neck is lower, you'll need more angle. Look at Perry's tutorial to see what I'm talking about.
Make sure you understand what's going on before you start putting things together and cutting things apart. If you don't understand, search or ask first.