Here's what I came up with for the fire suppression system: a PVC T-fitting as a tank, filled with water and compressed air, the latter forcing water through a valve (to be operated by servo) and through a drip system sprayer.
The white cap is the water fill tube. Fill the tank with a little water, maybe 1/2 full, then put the cap on. The clear tube is the air fill tube, with a valve to hold pressure in after filling. Right now it is kind of messy and inconvenient to fill and use. It leaks a little bit around the 1/4" hose fittings, and the valve has to be precisely off or water leaks out.
I switched from using 90° sprinker heads to a single 0.8gph fogger/mister head, finding that it was more than adequate to put out the candle, and is more efficient. Not an ideal solution... at least not yet. But, I feel better knowing that the idea more or less works.
It was cool to see, last night, the different approaches to sprayers at the SHARC meeting. Some really excellent ideas. More on the meeting later this week, as well as an update on Sparky.