Grow set up

you don't want tall plants, for sure. remember the double in size or more after flipping to 12-12 schedule. You'll want a certain amount of space above the lights +18-24" distance from canopy. You can work out your max height (sorry for imperial scale, but same path) Avoid that height at all costs... with good extraction, it should be fine. a taller tent helps with heat too -- larger volume for fan to keep up with before it impacts crop below. (like diving down in water you hit that line where it gets cold, but different factors dictating where it is, of course). 400w in a 1.6mtall... 1Mx1M area? you'll want the 400w for sure. maybe even run the 250 during bloom. Circulation fans are good inside your tent. I like to see a gentle rustling in my plants.. tells me air is flowing through it well.

A inline or "extraction" fan is used to exchange air inside ur tent. So pull old air out and new air in. A oscillating fan is used to move air around inside ur tent. Removing hot spots and moving air around your plant. Bot needed as they serve 2 different functions. As long as u can keep a distance of like 12-15 inches from ur 400 ull be fine. Take ur size limitations into consideration in deciding ur strain and or when to flower it. Remember plants can and will double even triple in size throughout flowering. If they get to close to the lights they will get burned!

I have a fan on the outside so it circulates air into the tent i use the inline fan 2 remove the smells with a filter and to lower my humidity or make it higher hope this helps im a new grower also