Durango Roundhouse Info Needed

I am looking for dimensional information related to the Durango Roundhouse as it was in the 50's.
I have Blazeck's drawings, but they are largely inconclusive for acccurate detail before stalls 7-10 were removed in 1971. In fact, the whole west end of the roundhouse is pretty much speculation from what I can tell.
Blazeck indicates that there are three distinctly different lengths. Stalls 1-3 are the original length, about 69'. Stalls 4-6 are extended about 10 feet longer, which would be about 79' overall. The last 4 stalls on Blazeck's drawing show that they are extended another 2 1/2 feet to what would be approximately 81 1/2 feet.
I don't believe that is correct. Most sources indicate that stalls 4-6 were lengthened at some point, but that stalls 7-10 were not, and still had the original brick walls like 1-3. The back walls of stalls 4-6 were either plywood or board and batten.
I know the roof over stalls 4-6 was raised in 1965, the Don Winslow photos from that year show the new wood above the doors still unpainted. I have pictures of #487 in 1967 housed in stall 5, one of the longest ones.
I'm trying to determine the length of the original brick wall on the West side. It might be safe to assume that the length of the west wall was identical to the South wall, which remains today.
I'm also trying to find the size and method of construction of the boiler house adjacent to the west wall. Was it brick or Wood?
Also, we know that the boiler room at Chama has two boilers remaining, one from a C-16, one from a T-12. How many boilers were at Durango and does anyone know their origin?
Thanks for any help you may be able to provide.
For what it's worth, I believe that the total engine length of a K-36 with plow is something around 74 feet, far too long to fit in any of the shorter stalls.