whats your temp in the room? even with the glass you need to have atleast a foot or more between tops and hood. veg to 12" and hope it doesn't get more than another 6" during flower and your good.
hood thickness about 10" you need atleast 16" from tops to hood. thats over 2 foot. dwc setup about foot tall. now you have maybe 12 inch of room for plant. unless thats what your shooting for.
I've had it 2 ways sometimes they just take the blood and test it later and all they do is prick your finger. and i've had them take a little vile and then the blood.
If you have a place outside you can feel good about put them outside. Sitting inside at the window isn't going to help them grow very fast or big. They need some real light. So if you don't want lights inside this is your best bet. Good luck.
Im not sure how well it will work with dirt in the rockwool.If you do this make sure the soil has been flushed well of nutes. Soil and rock wool can get saturated with too much nutes so keep this in mind when you water each time. I like to flush every other water change or nute strength change...