Don't starve it for voltage, that can strip the cathode in the rectifier tube among other things. If you detect no AC hum, go ahead and bump it up to 110-115. Just don't use it a lot and never leave it on unattended.
I'm one of those who believes in wholesale recapping. The old electrolytics might be fine--for now---but their failure can be catastrophic in more ways than one. You do
not want to have to replace that nice big power tranny, do you? Shorted 'lytics can toast it pretty quickly...so in case the rectifier plates are glowing orange, I'll just mention the fact that that's not normal.
Also the capacitors that block DC from tube grids, especially in the audio stage, can cause very unpleasant things to happen when they fail. There are a
lot of caps in this thing, but in the long run you'd be much better off to just replace 'em if you really want to use it regularly without worry.