One safe way someone pointed out in DF (this was a good tank and was nice enough to share this with us) was to make a triangle in the middle with the markers for M4-A8 (however you wanna call it) to make the missiles and stacking a no brainer. MTank just stays in A while the rest stack in B or C, once the missiles come down move to the other mark and as soon as you do that you all should be stacked to share dmg, rinse and repeat. Been trying to explain this one to people as well but for some reason someone likes to remove those marks and use them to mark the adds, which you can easily just mention by cardinal points and assign one dps to each to clear them. Well, they'll learn it one day but for now it is scatter for their lives and hope to make it in time for the dmg sharing in DF.

Even when knowing the fights blunders can happen, patience is key in these.