There really isn't that much RNG to the buffs. You're guaranteed to always have at least 1 of the healer or tank buff.
Most guilds do this fight improperly if they're unable to down sparks w/o the healer buff. You're supposed to have one side chain both bosses and then trash while the other side chains the trash and then both bosses. The side with the bosses at the time has the tank move into the center where the sparks spawn. By doing that, you're guaranteed to either have the healer be able to aim the waves at the sparks or have the tank scuttle to the sparks. It's not a coincidence that both buffs deal ~750k damage (in 10H at least). The only thing you have to keep note of is that the side that does the bosses second can't pick up their panda buffs right away because you'll risk the buffs falling off before you even start on the bosses.
Like other guilds, my guild would struggle with handling the sparks until we switched to this strategy. Sparks are just meter padding with this strat.
(To be honest I hate it when we get both the tank and healer buff because then our warlock and priests can't execute them for embers/orbs, but I'm just a DPS meter whore.)