My first grow, stealth grow.

https://www.rollitup.org/grow-journals/502378-stealth-grow-18l-containers-first.html

One of the first two leaves are yellow-ish brown at the very end of it, bottom side only.
I searched what I could, and I have found that I may be burining the plant with nutes. However I just raised the light (14" now) and it's starting to look better.

Could this be because I had my bulb too close?
**I can't get a clear picture of the colour of the leaf as my camera sucks.**

Any pro-tips to give? I'm going to buy a sticky fly trap and get some sugar+yeast CO2 going soon.

Would it be a bad or good idea to switch my lights every night, from MH to HPS and vice versa.
If I notice my top soil layer dry, is it okay for me to water it if the light is on? While avoiding getting water on the leaves of course
One other concern, but seems natural, one of the first two leaves are bigger than the other. Is this abnormal or is this fine?

Grow Journal : https://www.rollitup.org/grow-journals/502378-stealth-grow-18l-containers-first.html

Thanks

So my day two wasn't as progressive as I hoped for. Do you guys think that it's the lack of light? I raised it up yesterday to 14" above the plant, before it was much closer.

Can I water when the bulb is on? I want to say "Yes as long as you don't let water get on the leaves so they don't burn" but I'm not sure. Any thoughts?

What about that MH/HPS switch up. Is that a good call?