Your plants look fine, good luck! :thumbsup:
I think you don't have to worry about HPS, I use 250W for 2 plants, they are 20 days old now and look very healthy (however, I use a DWC hydro, probably it corrects some possible problems with light).
I keep the bulb at 60cm (24") distance from the substrat surface (but please note, I have 250W - in your case the distance must differ).
A few questions:
1. What are your plants strains?
2. What is about airing, what do you use?
3. Environment temperature?