You should note that the ACTUAL rules are something like 6 pages in that book. The rest are prescriptions, definitions, appendixes, and special rules for different kinds of racing. Read 'em!

Coming into the mark on Starboard is a strong approach to a downwind gate. It gets scary sometimes though with the closing speeds and things it takes to keep a spin boat under control during the rounding (and port boats that haven't read the rules)

Assuming that you are rounding the mark to port, the port boat has to give way to both starboard boats that have overlap - even if you're only overlapped with only one of them. It makes no difference if you are single handed - you should be able to manage your boat...absolutely no special rules for someone who chooses to sail single handed. Not only do you have to yield room, you have to yield right away and they should have all the room needed to make a fair rounding.

Though the port boat does have to yield to the starboard boats, it's not game over. The best approach for the port boat in this situation is, borrowing one of Rick's phrases, "slow down to win". Take your time, go a little deep, get your douse under control, let the starboard boats do their thing. You can bet on them making a slow fat rounding on the upwind side of the mark since they have to gybe and get the douse taken care of. If you prepare for the rounding and get your stuff together well, you'll be able to shoot right over them with an "enter wide, exit close" rounding strategy.