I know with 100% certainty that you'll be able to get a trade paperback sized book. I'm pretty sure - I'm waiting on some e-mails to get answered - that a mass-market sized paperback will be available as well. When I'm 100% sure, I'll post that as an update.
Nope - we want to make it easy for you. In the final survey, one of the questions will ask which size you would like. If you want two different sizes, make sure that you up your pledge enough to cover two books.
Don't see the answer to your question? Ask the project creator directly.