Battery tech now means u can use it right away, it makes no difference at all, I would just set it all up then put it on charge.
On another note I'm returning my iPhone 6, lovely hardware but iOS on a phone is just not for me. The Email experience for example is bad, I can't find anything as well down as the Gmail app on Android. Simple things like knowing which one of my email's something was sent too are messing, I just have a long list of notifications for everything.
Were you using the default iOS mail app or gmail app? Either way, they both suck for Gmail.
Use Mailbox, so much better.