I don't think the RFC are on the
DDP.
For an ADR, you will need to join the RFC Safari Club. It has a one time fee. But you will get that back in coupons and discounts.
Unless things have changed, a Safari Club member can give at least 24 hours notice and make a guaranteed reservation.
Or, make no prior res and go to the check-in podium. Safari Club members have the front of the line for seating.