This is the method I use:

First get some help to get the timber into position.

Having made a template place it in position and mark the joint. I have to admit I use a sharp pencil, I just couln't see the mark with a knife.

I then cut out for the tongue using a Ryobi chain morticer.


I then use a saw to cut kerfs, knock of the waste and then use a chisel and rebate plane to cut down to the line.

I am now thinking of a similar New Yankee Workshop style way of cutting a stopped splayed scarf. Any suggestions?
John