hmmm may have to re evaluate my targets sub 30 hours is possible if you can swim well and have the endurance of a donkey, i can swim a single iron @1:16, bike 112 in 6:10 and run a 51 in 9:00so if i just double the swim and bike figures and add about 20% as a degradation factor it comes to about 27 hours but my 51 mile run was done fresh so maybe i should judge it on my 70 mile average pace which is a fair bit slower so i think 30 might be a bit tight, im going to be crunching figures for the next 3 weeks 
DK, don't worry about your time at all. Get the training right in the next few months and upto the day and worry about it afterwards. I'm no expert however I witnessed a lot of the double this year. It's a different beast me thinks in in just doubling up your times and adding a bit. It's about control on the bike leading into the run.
Your 6.10 time was in Outlaw (?) maybe. Think of the numbers of cyclists around you at any one time in that event. Were you in company for a lot of the time and had wheels to follow or were not that far away? At AT you will be on your own for a long time as they isn't the volume of riders and those that are there are riding at such a varied pace. No disrespect to anyone but the difference in bike times between the French guy who won the event and others nearer the bike end of the field is absolutely massive.
The run will be hard. 48 laps will be one tough cookie to handle mentally with a lack of sleep. The course can be muddy at the bottom end around the lakes and then hilly upwards on the second half of the lap but you will soon get into a plan of where you can run and where you WILL walk on most of not all laps.
I loved the small, intimate feel of the event. Don't expect red carpets but you can be guaranteed a Schmunks cheer every lap. Steve and Eddie the organisers are there to help and will cheer you every step of the way.
Enjoy it and don't worry 