H1B premium proces.

1. H1B premium process refers to 15 "calender" days, rather than "business" days, is that true?

2. How long normally does it take for a company to prepare for those documents to apply H1b? when a company files LCA, could it files I-129 to the process center in the meantime, or the company must wait until LCA is issued? The point is, How quick all these could be done? because my OPT is due soon, I am worried about even if a company try to hire me, however, there is not much time to prepare all of these documents and file them to the process center before my opt status end.

Help!