I may not have an answer for you , but here's my thoughts. I only bottom water small starts myself. I set the small cups in water/nutes for 20 minutes , long enough to see they are wet , very wet. Then I make sure the extra water can drain and they don't sit in it. I won't do that again until I feel they're right next to bone day. I also don't do that every time , I water from the top to help flush the plants and make sure there's no salts building up. Again I make sure they drain well and don't sit in any extra water. Once plants are in 1/2 to 1 gal pots I DON'T bottom water unless I simply can't make the time to water from the top. And remember plants use the water at different rates. One may need water and another doesn't .
I used to raise African Violets and they use to have mold problems at times. I used the old time Lysol concentrate , NOT the spray in a can. Mixed like the instructions ... put in it a hand spray bottle and sprayed away. Kills the mold and never hurt the plants.
Peace & good luck,
P.Dreadie
What Jupiter said certainly wouldn't hurt . The idea is to NOT keep them moist all the time .