It doesnt really matter if u cant tune your guitar to perfect E. As long as it is in tune with itself.
as if some nerdy guy will pop up and tell you that you are flat or sharp.
and if there are more musicians around. you just need to make sure u are in tune with eachother.
who cares u got an ''perfect E'' when the rest of the band is ''in tune'' with eachother. and u pop in with ur ''perfect E'' you're going to have to retune buddy!.
(plus, every single guitarist i know always has a tuner with him...so saying something like : how can u tune without any strings is really irrelevant.)