Funny how as this project develops for me, I keep finding little bread crumbs from god. (Not sure if its Thor or Jesus) This is the only recently active volcano around this area, and it happens to be at the base of the red sea. I could not have asked for a better location to produce clouds.
The Jetstream runs due west from this point. If Saudi Arabia and Yemen lower some mountains in set locations to create a Jetstream to the north, the moisture created from this project should move further north, while also adding rain to the current weather pattern. Messing with Oman could stop the Jetstream from turning west, so altering mountains "downstream" of that turn will keep a good western flow, otherwise we will find much more rain in Saudi Arabia, and Africa will be depleted. I think we can water Saudi Arabia from the Mediterranean, so we can avoid major changes in Africa.
For example- I bet if we made a 300km wide path from Ash Shihir though the peninsula by Al Mukalla, and ran it inland, ending up along the inside of the mountain range to Amran/Sa'dah, we could create a nice flow of air across that valley, and it would shoot right over the nile in Sudan. I can already see some natural mountain formations that we can use to our advantage.
Drone Earth Moving Tractors.