I'd allow a couple of weeks minimum to get the ticketing sorted - you may be able to do this faster, but my last AONE3 took around this time to sort and ticket, with a couple of to and frows about flights to ANC. However, if you have a straightforward CAI-LHR-LAX-HKG-LHR-CAI that you plan to reissue later, you may be able to get it done in record time.

I personally like holding a paper ticket - comforting if you're at the dog end of a RTW in DPS and trying to get home. Paper is hard to dispute, but what are you going to do if your eticket has gone AWOL and you flights leaves in 40 minutes? (I may find out as I'm on my 3rd itin and have been foreced from paper onto 'E').

To avoid paper, the tip seems to be to minimise segments and avoid ground segments. My current AONE3 was LHR-LAX JFK-LAX, with my returing from the US from LAX and re-entering via JFK, this, apparently, is a no-no for etickets.

Good luck, enjoy, and don't forget to tell us how you get on!