In terms of which miles to use, DL miles are better for Morocco since the DL award chart places Morocco in the Europe price band, while UA places it in Northern Africa. 156K SkyMiles is enough for two r/t tickets in Y (60K each), although you'll probably fly AF/KL/AZ across the pond to get it for that number of miles. If you got up to 160K, you could book one direction in J (50K) and the other in Y (30K) for 80K each.