Variac

[VA561]

Should a variac always be used when beginning a new project? I have 2 16" zenith porthole tv's and a 12" zenith porthole that I hope to restore. If I replaced all of the weak or shorted tubes and wanted to see how the tv's performed before I recapped them, would a variac be the best way to turn the tv's on? Is what is referred to as a safe start? I'm trying my best to learn about the restoration process so any advice is appreciated.