I'll pour over the map later and let you know. From memory there are a few larger dunes all in a straight line for 20 odd klm. Think it might be south of 22.
Low pressures could be ok with your set up. An run down and back to 17 / Durba Springs would be a nice trip. They are outstanding places to visit. Allow 2-3 nights at Durba, you will love the place.