CRT size please

[6GH8cowboy]

I have recaped a Admiral 20Y1 chassis for another VK member and have been trying to resolve a "width" problem. (very slightly lacking). All caps and a few resistors later I just noticed that 10 and 12 inch CRT is on the schematic. The yoke assy is also at the top of the elevation travel. I'm begining to suspect that some one at one time put a chassis from a 10 or 12 inch set into the 16 cabinet with a 16" tube.
I have been all over this set and cant get any more width. All voltages look good and horizontal wave forms (PP) are up to spec also. I'm about a 1/4 inch short on each side. The focus coil was a bear to get right when centering the raster. The picture looks very good other than the width thing.
At this moment I feel like I'm trying to get water from a rock. (No disrespect to Moses).

Is my perception correct or was this a common, flexible chassis used in 16' crt applications also?

Dave