Each plant actually uses 2 buckets. The one with the soil has a bunch of holes drilled into the bottom. The second bucket does not. The hole bucket obviously goes inside the one without holes. This leaves a good 4-5 inch reservoir inside the second bucket for runoff to pool. It is a pain, but just before I flower, I empty all the runoff buckets. The runoff collects in a manner that makes testing its EC/PPM?PF really easy. Here's some pics from the build. The roots do not grow through the buckets holes for whatever reason.
The seedlings definitely stretched. Even when I sprout under the HID lights I get the same early stretch. But, in my dome the humidity is better and the heating mat underneath also add to speed up sprouting and germination. I always quickly transplant them as soon as the false leaves open fully. As they grow, I will add a little soil to the base so as to raise the ground level slightly. I once saw a grow that where the light was stuck high in the room. The sprouts stretched around 2 ft. The guy made the thin stem go around the bucket and lay on the soil so the stronger veg growth would be at ground level. He also covered the stem with soil. Interesting stuff.
It's important to match the amount of feed/water to the size of the plant. I've noticed that under a foot can do well with 500ml. I add around 500ml for every foot the plant is above that. So, 2ft- 1000ml per feed; 3ft. 1500ml. per feed; 4 ft - 2000ml per feed. I feed every third day. (Nothing nothing, feed, nothing, nothing, water, etc...) Really, its more of an instinct than those exact amounts. But those are rough numbers. With those amounts small plants don't get over watered, and bigger girls get a thorough soaking without much runoff being wasted. You can hear when water drips through one bucket and into the other. That is a great indicator that you have saturated the soil. Some strains drink more or less as well.
I am anxious to try the White L.S.D too! Glad to have you aboard. I have 3 600w MH/HPS dimmable set-ups in the larger room. Each covers a 4 by 4 area. The buckets take up exactly 1 square foot a piece. Math is fun.
-Dude