This has gotten long and perhaps someone has suggested this idea....

Just cross his bow and burn him.

Go back to your original story - you are on port but can't clear the starboard boat without "fouling" him. Why not go ahead and cross his bow? You hold your course for the time it takes for him to make the protest and you sail on long enough to get back to windward of the layline. Now do your 360 penalty turn (very quick in a monohull) above the layline.

This seems faster than what you did, "We had to bear away, gybe, come back to close hauled, run for a short bit on port, and then tack back for A (naturally, after letting some traffic by that was coming in on starboard)."

Better yet, since you're right at the mark anyway, tack back onto starboard and wait until after you clear the mark to do your turn. If you wait until you round the mark (as lead boat) before doing your penalty turn you could sail above the mark and do you're turn in clear air, clear of traffic, and you'll foul the air of any traffic as they round and head down and try to launch spins. However, since you were first around the mark you might only lose the one place to the boat you fouled as you do your 360.

Sure, my way is a foul but my way took FAR less time than yours. Racing is to win, not to lose. Doing a penalty turn is playing by the rules, too. Saying you're sorry is better than saying congratulations.

OK, my flame suit on.