One in, one out... simple rule for ventilation. Keeps the pressure the same inside the tent.
Tent gets the climate from the room it stands. You have that in the right RH range, only to little ventilation can give your plants a issue. Beware the dark times... run a log for RH, so you know you stay below 68% all the times.
I would go 2 x 150mm inliners... one in, one out. And count 4 oscillating fans to vent plants and lights. If you use your intake clever, 3 will do. Hang em, no loss in ground space
Light wise you should be fine. I work with 410 to 480 watt per 1.2x1.2 section. No complains harvest wise