New grower...250 watt MH question

This is my first grow, how soon after my seeds sprout can I move into my grow room in the basement under a 250 watt MH light (I'm growing 2 plants)? They just sprouted yesterday and I have them in my loft under a sunlight window.

One more question.... Right now I have them in little containers with organic Jiffy seed starting mix. When should I move them into regular soil. The soil I have is Miracle Grow Organic Choice potting mix. Ive read different opinions about MG, should I just go out and get a different type of soil?

Thanks

You can move them down there right away. Probably best.
I start mine under 100 watts T5, couple days later I got them under a 400w light.