Submitted alteration packet - What next?

I would give them 2 weeks

Not sure if all small co-ops work the same way, but in my experience your drawings will be reviewed by your building's architect who will have several comments/objections to your plan. They could be small technicalities or a big deal, but unfortunately it's in their best interest to have more issues since you're paying for this review.

Then you go back and forth with him/her until all these are cleared, and only once all these are out of the way will the package reach the co-op board.

You may not get any decision from the board until after their next meeting.