SAMS dates it from 1954, about a year older than the stromberg carlson i found, which had a CRT that tested strong, so who knows, will have to see what happens, it IS and oddball size, but there are options.
70 degree deflection angle.
the B version IS aluminized.
as mentioned magnetic focus, with perm mag rings.
on the VERY outside chance that it's bad and or can NOT be made to work, and i deem this unlikely, but you never know
ETF has a 21XP4 which is ALMOST the same, Low voltage focus & slightly dif dimensions, with a bit of creative bodging, can be made to work, it's not THAT different in size, would have to adjust the border and mount a bit, and create a volt source for focus, but I seriously doubt this will be a problem, but I have researched it!