to confirm - as an ex-Sharm instructor with hundreds of dives in Ras Mo:
All dives in Ras Mohamed are "drift dives" because there are no moorings, however, as Solly says, which way the current goes (or even if there is any at all) will be dependent on the conditions on the day, Ghozlani is usually a mild current running south to North, Za'atar is a wall/corner/slope which usually starts at the wall with mild to no current, the corner has current which is often against you and then the slope has a mild current against you which is no effort to manage and so you pootle along and then turn and drift back towards the corner after 45 - 50 minutes of the dive (well, that's what I used to do, anyway).
It's not always drifting, more like "go in here, come up there", whether there is current or not. Shark and Yolanda is a must-see and the normal current direction is from Shark towards Yolanda, but NOT ALWAYS! If it's going the other direction, and you jump at Shark, it can be a most un-enjoyable dive. The current can pump there big time, in either direction, or both, and any decent dive guide will ALWAYS make a current check before jumping with their group. As in - physically get in the water and see which way the fish are swimming, not just have a quick look over the side. I'm really anal about this - if your guides are not jumping in to check the current at Shark and Yolanda, they're not doing their job properly! I would check at all but a few sites, and the only ones I wouldn't check would be Near, Middle Fiddle Garden, and White Knight - because it's usually pretty tame, and it doesn't really matter for most of the dives at these sites.
You don't need a drift certification; most people don't, and if they do, it was just the Drift Adventure dive as part of their AOW course.
Hope that helps,
C.