I'll give the timing thing a try. This 600 Jr is much different than the 650 I learned on as a kid. I have one for 12 gauge, and a Lee for 16 and 20.
I know one of the things done back in the day was to machine the charge bars to accept Texan bushings. I have a boatload of bushings, but the charge bar I have that is machined for them is for my 650.