In 10 man version of the encounter I find it easier to have the 3 ranged just collapse into melee to get the innoculated. Just have the two spores stand one or slightly behind the tank, and the other on or slightly behind the melee DPS at the back of the boss. No one should be in the middle of the boss and get hit by both spores. Once the sport explodes, you have 8 seconds to run back out to range before he will use Vile Gas. If both are on the melee side, one of them moves over to the tank side of the boss. If both are on the tanks, the inactive tank moves to behind the boss by the melee DPS. Having the 3 ranged people move 10 yards to get in range of the spores on melee or tanks is just as easy as having them collapse from 10 yards apart onto a ranged spot. Only difference is you never have to worry about 2 in melee and needing one of them to stop DPS and run out.
"In anything, if you want to go from just a beginner to a pro, you need a montage." /w TankSpot WTB Montage for Raiders.