No offense, but wouldn't it be easier for your raid to just learn where to stand and how to do the encounter?
BigWigs (maybe DBM, too) has a proximity window for people to make sure that they're not too close to each other.
My old guild had used a strat on a site that actually gave in-game screenshots of what each spot looked like for where to stand - it was very helpful. On my first Gruul's run, I knew to keep my proximity box empty and exactly where to stand. Unfortunately, it seems that the site no longer exists.
But there really is no substitute for experience and your raid members knowing what they're supposed to do and when.