Bruce,
A #4 really does nicely on any outside horn Victor, I use it on my Vic V and Schoolhouse almost exclusively, so much so, that the Exhibitions these machines came with or more or less just on the machines "for looks" when I'm not playing them!
Some time back, there was an ebay seller (Randall Anderson?) who was selling a nifty little adapter so you can fit an Exhibition, #2, or #4 to any ortho machine and vice versa. Unfortunately, I never bought the one for the ortho soundboxes, but the one to fit these on an ortho machine is a lot of fun. I use it for playing acoustics on the Credenza et al using the #4 reproducer and they really come to life this way as well. I even take it one step further (call me OCD) and use my Hughes stylus and this way can play Pathés on any orthophonic machine!

Anyway, #4s are very nice reproducers indeed!
Sean