Seedling HELP (Flood & Drain Hydroton)

I finally sprouted a couple seeds (afghan) in rapid rooters!! but i have a few questions! I used rapid rooters to germinate/sprout in a dome/tray and used a water bottle to spray and keep everything moist.. then after a week i transplanted to the hydroton. the bottom of the rapid rooters are like 1/4-1/2" from the flood level. I’m using an a/c 400w hps, like 10-12” from the tops on 24/7 and flood every 4 hours in 1 gallon pots. i already know i fucked these seeds up from over watering (they are drooping a bit) and transplant shock, i transplanted them on the 24th and like no vertical growth has occurred but the leaves yellowed a bit so i gave them 200ppm of maxigro and i think they’re just recovering now. but i have 2 more I’m transplanting tomorrow so i want to make sure i don’t mess things up on 2 new ak-48 seedlings, so heres my questions...

1. Once transplanted, should i water the rapid rooter directly? i was using a spray bottle but wasn’t directly watering the plug, just around it. also, should I still be flooding every 4 hours when watering from the top?
2. How often should i water the top? when the plug is like really dry, like a beige color? or when its still kind of moist (light brown)? or should i just not hand-water them myself at all and make the roots stretch to the flood level?
3. Is it safe to transplant into the flood table at such a young (1week) age? some people say to wait till the roots develop but logically i feel like the more roots sticking out the sides and stuff, the more damage can be done and more shock when transplanting. any thoughts?
4. Should i put hydroton on top of the rapid rooter when in the pot or should i leave the rapid rooter uncovered?
5. What could be causing the tips of the taproots to turn brown? the taproots on the afghans were brown and skinny/shriveled. i read some places it could be from light hitting it or under watering and some other stuff too… or maybe my heat mat?
6. Also, i have a thermostatically controlled heat mat. when should i take it off?

Sorry i typed so much but i would really appreciate if you could help me out!!! thank you!!

1) Water the RR directly until the roots are able to feed from the flood table.
2) Water from the top 3-4 times a day. I would say do it as many times as you have your table set to flood.
3) Placing the plants on the flood table is tricky. As the table floods the RRs will float. The plants will not be stable until they have pretty massive root systems. I use small plastic hydro pots filled with hydroton instead of placing the plants directly in the hydroton in the table because of this.
I have grown lots of veggies using the direct in table/hydroton technique, it works but there is a lot of shifting during the floods.
4) Place hydroton on top for stability and light blocking.
5) Roots can turn brown for many reasons, in your case I bet it is due to drying out.
6) I never use heat mats so I would say take it off...this could also be a contributing factor to your brown roots.