On my Gibson LP, the tuner centres are 35mm apart, with the two E tuners spaced 64mm (2.5") from the headstock side of the nut.

The PBG pre-drilled headstocks have the two E tuners at least another 10mm away from the nut.

So I'd be driven by the shape of your actual headstock, as the Gibson measurements may look wrong if the headstock is longer than you'd expect. But 35mm centres is a decent value. You don't want to go much smaller than that.