The lucas formula is 1 part micro and 2 parts bloom. In the strength you need it.

Not just to stabilize. Think of the weight of the plant and gravity pulling straight down. A neoprene collar will not work. The purpose of hydrotron is to keep air flow and hold just a small bit of water. Another good medium is lava rock, like for the gas grill. Just beat it up with a hammer to the size of marbles. Just as good lots of air and stable root mass. Normal rocks are not good but may work.

Wait till you have roots coming out of the peat on the sides and bottom. At least a few roots showing.
Seedlings don't need food untill they are about 2 weeks old. No matter where they are.

Upping the nutes to the week before harvest. Till you see the tips of the leaves burn and then back off just a little. A flush with PH water the last week.