The problem with 400s is that they have a really small footprint (roughly 2' x 3' for optimum lighting) and not a lot of penetration. So, even with 3 of them you get an area around 3' x 6' and some areas are going to be far darker than others. Not a problem if your leaving some shuffle room.
2 600s would give you the same wattage with deeper penetration and a combined footprint of around 4' x 6' (side by side). Or 8' x 3' (end to end) leaving an aisle against 1 wall to move around.
You could do 2 1000s but if you have to downsize itll be by 1/2.
If it were me and $ wasn't a problem Id go with 2 600s and a 400 in between or 3 600s - side by... You could also put a mh in the middle for increased spectrum.
Just some ideas.
2 600s would give you the same wattage with deeper penetration and a combined footprint of around 4' x 6' (side by side). Or 8' x 3' (end to end) leaving an aisle against 1 wall to move around.
You could do 2 1000s but if you have to downsize itll be by 1/2.
If it were me and $ wasn't a problem Id go with 2 600s and a 400 in between or 3 600s - side by... You could also put a mh in the middle for increased spectrum.
Just some ideas.