I put my distributor in with the number one piston exactly at 38 deg before tdc on compresion stroke. I turn the oil pump with a screwdriver to get it to drop in exactly right there...then turn the distributer wherever I need to to get it pointed exactly at the prong on the cap...timing is perfect as soon as I start it.
I don't understand the NEED for an adjustable rotor :?
Once you get the distributer to fall in by turning the oil pump with a screwdriver...the engine is still sitting 38 deg btdc so when you turn the distributer the rotor doesn't move...and since the cap has a locating notch to put it on the distributer the same spot every time you can just turn the body of the distributer until the prong in the cap lines up perfectly with the tip of the rotor.
JMO...works for me. If there is something I'm missing tell me because most of you been doing this longer than me...but I usually don't even need to touch the distributer after I start it ...I still check it though
p.s. obviously this won't work if the advance isn't locked out.