Thank you both for your responses. I had the feeling that scarf joint would not be able to take the bending stresses in the ridge beam.

It is good to know that the traditional solution is a ppost supported corbel. However, we do not want a post in the middle of the room (it's a small one room structure) so the corbel is out.

We are intrigued by the idea of a truss. What might that look like?

We are also thinking about the potential of using metal fasteners to support the joint/splice. Any advice in that direction?

Rafters ties won't work because the side walls are about 5' high. 53 degree roof pitch. What about collar ties?

As for beam sizing, the roof will be quite light. 5" round salt cedar rafters supporting a thatch roof and no snow load.

I am on limited internet so can't upload photos or drawings but will try to soon.