Blam and Blender

Blam addon for Blender.

http://stuffmatic.com/blam-blender-camera-calibration-toolkit/

Pretty amazing results.
From a still from Google Earth streetview, made this dxf file.

PARALLAX DISTORTION

So here's my dilemma, liberal arts, no math above Alg 2...Trying to solve a trig problem....Trust me, I kinda get it......
I start with a street view of 16 Cook St, Liverpool, and calculate its probably 26' across.

Now to get a height and proportions of the building, I take this, the best photo and start drawing lines on it.

ABCD are the red lines of the buildings with a square rec in magenta.
Actual A and D are known dimensions. B=C. Use the angles of the parallax distortion to solve for B. If I get the factors I can solve.
Are these enough variables?
Uses the same formula to solve for the middle lines?