Not 715, the 710, my typo,...
Yes the circuits will lay out almost the same, the hivolt transformer is different but the electrometer tube is still a raytheon unit, the resistors and pots are Stackpoles, hi-megs and the chamber are still Victoreen's own,...
the trick is tracing out the circuits and cross referencing part numbers,...
that's where the 710 manual helps out, you can only put these analog units together a couple of ways, and victoreen was consistent throughout the analog days,...
If Dr. PF is still working at ORAU he might actually have what you are looking for,...
But he is a Dr. and a very involved man, so you need to be very respectful about imposing on his department's time,...
I'd let ki4u deal with it for me, then again, I only have so many minutes left on this side of the turf and I'm getting a bit selfish with them,...
best of luck,....
GLW