Nice!
Those Schmidt mirror CRTs are really a work of art. Advent used similar CRTs on a very early model.
http://www.walvisions.com/ArchivePag...m_brochure.htm
It will not be very bright on a painted wall... I suspect that the curved screen that came with that model was similar to the Advent screen and had high gain (but narrow viewing angle).
Years ago, I repaired an Advent VidioBeam... It was a hot night, so I set it up in the driveway, projecting on the garage door to test it. It was dim, and the convergence was poor in the corners, due to the lack of a proper curved screen, but looked pretty good. I set up a couple of chairs, popped a cold one and put on a laserdisk movie. Turned out to be a real traffic stopper!... people driving by were totally taken by the huge video picture on my garage door.
jr