Hey Dave, this process is very quick. Once I got the jigs set-up I had all of the notches done (6 of them) in less then half an hour and that included cleaning them up with a grinder.
I did a quick mock-up of the new lower rails and crossmembers to see what the fit-up looks like. The notches came out great and I have some really nice, tight fitting joints for welding.

A couple more...

I still have to clean up all of the welding surfaces yet, this is just a look see for fit-up. I will go over all of the joints with a flap wheel on the die grinder to prep for welding...
Mark