With four days set aside for the Race, how many legs should I plan to fly each day?

It depends! Things can happen – that is one reason this Race is such a great learning experience. Mechanical problems can surprise the most meticulously prepared airplane (and racers). Pilot fatigue can surprise you and should not be ignored. The speed of your airplane is another factor. BUT, Mother Nature (the weather) holds the trump card for all flight planning.
Some years the wind and weather favor flying three or even four legs in one day, as long as both you and the airplane can be at a Stop at official sundown. Other years, it makes sense to hang back and complete the Race on the final day just before the deadline. It takes strategy, planning and adjusting to conditions as they develop.