Couple people to thank in advance,
@1971 Demon and
@Oldmanmopar
Demon gave me the measurement of 1 7/16" from the Duster emblem to the center of the hole
Oldmanmopar had posted a picture of all his adjustable rally mirrors that had the control cable retainers that bolt to the door frame, they included the cable retainer bracket that keeps the window from catching them as you roll it up.
I fabbed up the retainer, bent it up 90* and welded a nut to it, ended up grinding the outer edge pretty close to the nut so it would fit inside the door.
Turns out the retainer nut that i got with these mirrors, MB1247 is not correct, I Have ME754 on order
I remembered I had ordered MD3600 retainer previously, one of those, I know i ordered that thing, now where is it, lol found it
They had MN3134 LH Mirror Reinforcement plate on hand, so that got installed, the passenger side is on back order, so i'm thinking of mounting it with large fender washers underneath until that plate comes in.
I checked, they have no ETA on it at this time.
Going off your pics Wyman, it looks like I could have went a little further forward with it.
Hope this helps someone wanting to add a remote control rally mirror.