I made this sliding jig years ago for my table saw fence and have a stop screwed to the right at 90ยบ. You could make something suitable for your router fence and add a stop for whatever angle you decide on. Then use your dovetail bits. You would need a larger stop than what I have to support the wider boards. Heck you could also cut the splines with it if you had a small enough straight router bit, Just change the angle of the stop.
"Duck and Bob would be out doin some farming with funny hats on." chrisstef
