D45 mirror reinforcement arm/bracket

[oldgold70c10]

Reviving a dead thread here, but I am currently in the process of replacing the standard car-size mirrors on my '83 with the D45's.
The outside mirror bracket which goes on the doors is the same L & R. The bottom mounting hole is off-center. Hence the reason for the passenger side support which goes inside the door being longer.

As for the mounting location of the mirrors, I think I found out how to determine this relatively easy.
Inside the door under the vent window is a reinforcing plate where the standard mirror mounts. This plate has a hole in it with no hole n the door skin. Drill a hole thru the door skin where the hole in the backing plate is and this establishes the front top mounting hole for the D45 mirror bracket. Drill this first hole and then mount the bracket and get the top edge parallel with the window sill and drill the other two.
The hole in the inside door skin is already present for the support reinforcement.

I hope this info helps because there is very little info about this online.