Just putting this here, but will 5-15 minutes be enough to compile all the decks, merge them into a banlist and then put them up and announce them both in the thread and in chat? The last time I did that in a tournament as a TO it exceeded my expectations. Furthermore this is a one-person task, so make sure that all the people send their banlists to the same person in chat. The bracketmaking and newbie checking should be given to a second TO on spot, so that the first one has more time to deal with the lists.
Enough TOs will be there to make sure we have the work splitted as you mentioned.
As for the 5 minutes, this may indeed be a bit few. I tested it with 13 lists and needed pretty much 5 minutes, but without posting and so on. As it is today, I don't wanna change the times, though. The time for deck-building will, of course, be delayed if I need a bit more.
I also expect that most ppl will try to get extensions to build as it willl have 15 mins buildtime only
I can't imagine a Speedbuilding-Tournament where we had more than 15 minutes for deck building; we usually make 10, but this is gonna be a bit trickier, so I raised it. I think, it is fine. However, if more people agree on your opinion, I will increase to 20, but more won't be given. It is speedbuilding after all.