[Scale-planning] Tracks - do we have ways to determine interest when sizing rooms?

Hi,

We've been discussing various track proposals ( Open Data Science and Civics ), and OSSIE ( Open Source Software In Education ).

Curious what tools we have available currently to help us right size the rooms.

I know other events ask people to submit their interests during the registration process, or shortly after ( also allowing people to build their schedule ).

For example So Cal Code Camp produces a bar graph which everyone can see during the process, this helps also determine which sessions will be given a particular room - so far from my experience they've had plenty of rooms, so no one has been rejected a room.

Thank You Matti