Just want to say I agree with Soaring... I've done several distant attunements and make sure all my students have access to me, full manuals and full understanding of every aspect of their healing practice. Yes, there are drawbacks because it *is* much better to learn one to one, but equally you can get bad teachers in person as well as online!
As an example, I know of one teacher who just handed over a few photocopied pages and told them to get on with it...
One thing I wouldn't do is attune a master online... I'd prefer to check them out in person and make sure they'd do a good job.