Absolutely, I mentioned earlier...watering from the bottom is the best way, I let mine sit in the trays for as long as needed, if one tray dries out quickly, ill add a bit more. Those in that tray must very thirsty. I would only water a little bit from the top, not much, let the all the tap roots and such stretch to the bottom where the water is and the oxygen roots stay on top where the soil is dry and oxygen can get through. If the top is always soaked, the plants tend to suffocate plus your providing a perfect environment for fungus gnats, by leaving the top soil wet/moist. When they are young, yeah, they need more watering from the top to ensure that they are getting as much as possible, but once they are a bit older and their root system has filled out, you can water the trays, and they will soak it up from there...I'd say fill the tray about 3-4 inches high about, depending on what stage...when they are in full flower mode, they use alot more water, so you just have to figure out what they need depending on what stage they are at.
One thing I like to give seedling & clones early on before making up a full batch of nutes is Bio-Tone Starter Plus, its an All Natural liquid blend that helps with transplanting etc..Try to look it up on the net, you can find it at garden suppy stores etc. This stuff rocks, I have seen explosive growth about 3 days after using this stuff. It really only needs to be used early on w/ seedlings/clones and a little bit into veg, then I stop using it and go w/ my normal nutrient feeding schedule. I copied some info about it, since we can post direct links..
Bio-tone® Starter Plus 4-3-3
All Natural Plant Food Enhanced With Bacteria, and Mycorrhizae
Available in 4 and 25 lb. Size
1 pound equals approx. 3 cupfuls.
Microbe enhanced all natural plant food
Includes both Endo & Ecto Mycorrhizae
Grows larger root mass to help plants establish fast
Promotes bigger blooms
Reduces transplant loss
Non-Plant Food Ingredients:
Contains 1,341 colony forming units (CFU’s) per gram of 7 different species.
Ectomycorrhizal Fungi: 97,440 propagules per gram:
Endomycorrhizal Fungi: 2.64 propagules per gram: