I've been on ten liveaboards the past five years in the Red Sea and been to the Brothers three times. Mostly we went in March and in the fall, although at the end of Octobre it gets quite windy and the waves get higher. We always dive Nitrox overthere because with 4 dives a day it is saver. On the normal liveaboard Max. Depth (law in Egypt) is 40 m unless TEC diving, which is moslty restricted to the all the people on certain trips. I've never seen people doing trimix while others were i.e. on air.
Most often the Oxygen level in Nitrox is around 27-30%. Checking it is very simple, I always do my SO's tank too. Changing the computer to the actual level is once you know how very easy and as between dives, there is plenty of time, not very time intense.
On average, depending on your skill's level, diving in Egypt is very relaxed. If you want to be guided, fine, if not, that's fine too. Off late it has been rather quite in the Red Sea as a lot of tourists stay away due to the conditions in the Sinaï. But there is no danger so far in the Red Sea area. If you have more question's feel free to pm me.