Based on the question you're asking, I'd recommend that you look a little deeper into the construction methods before you buy any tools or jigs.
Full splice construction isn't rocket science, but it is very specific. You will need simple but specific tools and techniques to do it well.
In order to know what you really need, you first need to know all that you can about it. The fact that you asked "what is the cut angle" tells me that you need to learn a lot more.