I mean, I calculated the best average angle of the front of the cartridge so that it is positioned tangentially with respect to the arc of the arm across the playable disk surface...
I will warn you, Grado cartridges are sibilant, at least in my experiences tinkering with them. It's minimized at best, but, I'm yet to make it vanish on my Yammie or any other table that I've owned.
Also, I don't know if the 1200 arm is low or high mass. Do you know the compliance of the cartridge? If it's a lower compliance cartridge, you want a higher mass arm, and vice versa. I don't know anything about the older Grados, all I have for you is general info.
Good luck Ed!