In that size box, Kit #5, I would use two heat packs, yes. Make sure they are well started before putting them in the box. We typically shake them up very well then keep them in a folded towel for an hour or so before boxing them up. You want them already warmed up and chuggin along!
You can print your label anytime, it does not expire, but can only used once. Book the label from your computer and print it out now, or book it now and log into your account the morning of December 5th and print it out then. Or book it the morning of December 5th, it only takes a couple of minutes to book your label. You can print it out as often as you need, but again, can only be used once!
You can drop off your package yourself at the FedEx facility, or we can schedule a driver to pick it up from your home or office. You can schedule a pickup a day in advance. A pickup is $5, dropping it off yourself is free.
Let me know if you have any other questions!