If you plan on being indoors a lot, you could get away with 13 oz weights. I've been to that region and it seems everywhere is heavily air conditioned (malls, office buildings, restaurants, airports).
Definitely look at the 8/9 oz fresco too. That stuff will allow you walk around outside in the heat at length
Although flannel was originally a warm weather fabric, I think it would look strange in this day and age walking around Abu Dhabi. It evokes images of cold winters.