I do use a dome cover. Oops, I just told someone they could keep their chamomile! What does the chamomile do? LOL! I have used cinnamon for damping off but I haven't had many problems since I started using seed starter mix.
I have a sprayer I used also. I had to get one. Last year I made the mistake of planting all my coleus in one plug tray, albeit labeled very well -- hmm, I didn't have a sprayer. Flushed those tiny seeds all over the place. Needless to say, the tags were useless! So this year I got a sprayer!