I think there are a lot of folks reading this section, but apparently don't respond as often to things as in the Royal Caribbean section. Perhaps more RCI cruisers use this site than Princess, but I know we have many happy Princess cruisers who do access this section, although perhaps not every day. Having your question answered within 10 hours is a pretty good response, actually.
Princess usually starts working on their guarantees when final payment date has passed, although it's hard to say on exactly which day prior to cruising any particular sailing is completely assigned. F-mattox is right that you should have your cabin assignment outside of 30 days prior to sailing, although cruise lines claim they CAN make assignments as late as week of sailing. I've never seen Princess wait that long except in cases of people booking close to sailing.
Thanks for helping to keep this section active!