How much to mill Ford Rocker posts?

I have a set of C9OE 351 windsor (1969 rail rocker ) heads that I have been working on the last few months.Now the tricky part, How much to trim off the rocker posts to install guideplates and screw in studs? Ford tech says .230 yet Pat Garhal 's book says thats for just studs, no guide plates.Some guys on the net have taken the sometimes suggested .300 off only to have to replace the ARP spec'ed Ford rocker studs with the longer ARP Chev studs to get enough thread adjustment.I only want to do this once, any one been there , done that?
Great site people!

It's .300 if guide plates are going to be used on the head and
.230 if guide plates { ARE NOT } going to be used on the head.


~ Vegas ~