A Tale Of 3 Covers : West Indian Aerial Express 3, Santo Domingo To San Juan

Hi all, I am still having a blast! Such a great way to keep the mind busy in these difficult times.
Here is one I just put together. The West Indian Aerial Express has caught my attention since Kimo posted a Lindbergh cover a few months back and I have been on a roll. I believe I have sourced about 15 of them to date. This WI-3 (Santo Domingo to San Juan) seems to have a few variations. The top was post-marked the day before the actual flight with a large postmark where the second is a smaller. The bottom is a variety that seems the most interesting. From the seller I have found this (all back markings are correct):
Cover being offered was carried on first mail-carrying flight from Santo Domingo to San Juan. It is autographed by Rowe, who was the pilot on the flight. Part of the carried mail had missed Santo Domingo departure cancellation. To make up for it, Rowe had arranged for such covers to receive a courtesy San Juan cancel. This resulted in unusual-looking covers on which a Dominican stamp is tired by a US-style San Juan cancel. For a specialist [Muller 3var, AAMC WIAE 3var].

I am still looking for addition info and believe it is will be found in a later edition of the AAMC than I have.I am also still seeking out that plastic bound book : A philatelic guide to the postal history of West Indian Aerial Express and Pan American Airways, 1927-1931 by Norman Alan Cohen.
All additional input welcome and thanks again for indulging me...

I would recommend that you go to your local library and get them to get for you on in inter-library loan a copy of the book "Under My Wings" by Basil Rowe published in 1956. Basil wrote this book as his autobiography with his insider stories. Or you can sometimes find it on ebay or such but do not pay more than $25 to $30 for it. Occasionally some insane seller will try to get hundreds of dollars for a copy but they are just delusional.

Thanks, Kimo, I found one, a reader for $20