Yeah, I know. Corney. Just like all the other post titles...what else did you expect? Anyway, the next step was to build the 45-deg jig for cutting those neat looking slots for the splines. The jig itself was easy enough to make. I thought however the instructions in the magazine article were not so clear as to actually how to assemble the jig. I think what was missing was a diagram similar to the angle shown on the left.
The idea basically was to simple stabilize the box on a 45-deg angle while allowing a story stick to align each of the places where a spline was to be cut. As the article warns be sure to cut all 4 sides and then that same spline position on each box if you want them to all look uniform.