Most libraries are made with a specific drill and the diameter set to automatic. So you can either change the pad size in the library directly to a fixed bigger value. Or you change it while doing the layout. Go to the DRC dialog, there is a tab called 'Restring', you can scale it with that setting.
And now I realize you are talking about the holes and not the pads. Anyway, I'll just leave it here.
For holes: open the library and modify the relevant package, that means each single pad ('group' to select all pads at once will go a long way...). But I can assure you, if you use the RCL library for example, those holes are more than big enough. All I normally do is increase the restring in order to have bigger pads. If you get those boards produced, 0.8mm is big enough and fine for that standard 0207 resistor. If you drill yourself it doesn't matter anyway, just use a 1mm drill (+ bigger pads), so you don't get in trouble with misalignment. But that's only a problem with ICs and not resistors or caps. And that's why tonepad and ggg layouts have bigger holes and pads to begin with, because they are meant to be etched and drilled by hand.