Zoho Sheet

Hi there, this looks like a great system. I'd like to use it and would even pay a moderate fee. Sadly there's not a lot of information available. I went through the Zoho sheet entrance which said some things but left obvious question unanswered, eve trawling through the forum didn't help. Simple questions need to have answers upfront E.G. What is the maximium .xls file size? Is it private? (I want ONLY me and my friends to be able to see it) Is there a cost involved? is it per user or MB size? If so How much? In my case I have one workbook that is currently 2.4Mb it will grow to 4Mb I want to be able to edit or re-post and I want 8 others to be able to view it But I need it to be secure from prying eyes. I tried to upload a a 2.4Mb file it would't work.
Regards
Mike
mikepugh