Yes, you can always update that later; mainly, I just need people who want the big boxes, etc. to fill that out so we can get a count on the number we need to produce. The backerkit will be open until September 1st. There will be email/update notes and reminders along the way.
Any notice you get from backerkit is just a note to remind you to fill out your survey if you hadn't yet. It won't be locked down.
Bt