For the elevation of the bleacher according to the drawing it is 11’2". But it’s not what is actually happening based on the footages.
Based on this image of the North bleacher I measured the elevation 0.1m (0.32’) less because it is not supported by the wheels but by hydraulic jacks. South bleacher is also supported by hydraulic jacks.
Another difference I found from your measurements is the elevation of the bleacher. I’m using this position (40.856805, -79.971099) as reference where the ground support of the Jack is. The elevation here is 406.8m or 1334.65’.
Also, the dust footage of the first bullet indicates that it hit the vertical rail 4" below the top of the rail.
So just for these three corrections we get -1.69’ at the bullet elevation on the rail.
Because Trump is much closer to rail (23.88m of horizontal distance) then Crooks (141.05m of horizontal distance) an error of 1 foot at rail results in 5.91’ error at Crooks position.That results in the bullet coming from 10.02’ above your elevation at B6. That will get you more close to Crooks elevation.
I don’t believe that Google elevations are very accurate so that’s a problem that could only be solved with measurements with total GPS stations.
The lines of sight tell a better picture, look at this footage for example.
It’s is taken at an elevation of the eye around 1.6m and the person this footage is between the fence and B6. If the bullet was fired from this footage elevation it would come almost 2’ above the rail. That also tell that the bullet comes from a much higher elevation from this footage alone.
I also did a study for James Copenhaver footage almost 2 months ago. I still stick to the results of this. The estimated position of the bullet fired from Crooks position hits very near the rail.