Hi there! I would recommend that you divide the large plant as late as you possibly can - and yes, if you want a division that will bloom sooner, have a minimum of 4 psuedobulbs, the more the better! Water the division well before you leave to head home, and just take care to not injure it on your journey. Pot it up when you get home, put it in a low-light spot for about 5 days after you get home (because it will have been extremely stressed) and then put it in a normal growing place and leave it alone. If you take proper care of it, a catt will make a valiant attempt at life and will put out some sort of new growth for you within 3-4 weeks, so let it decide what it wants to do. Good luck!