There's a similar product called Mosquito Bits which are just Mosquito Dunks in granular form. They have the same effect but no need to break them up. One bottle should last the entire season.
https://www.amazon.com/Summit-Responsib ... YORO&psc=1
As for using the self-watering pots, they should be fine although you won't be able to directly tell the water level. You could also just make your own self-watering pots by getting a bucket and drilling a hole a couple inches up the side. That would give you largely the same effect.
My problem with either of these approaches is that the water will quickly go anaerobic and essentially becomes unusable by the plant. Sarracenia don't seem to mind too much but other plants may.
Then again, better to have anaerobic water than dry soil for these moisture loving plants.