I've got a 120 X 120 X 200 tent and I only ever do 4 under a 400W dual spec. I have crammed 9 in there before but I get more now then I did then and had mold problems too.
I'd go with the 4 if I was you.
I've done both and the quantity of bud is greater with hydro and the speed of growth is too but the work is much greater and the bud does taste more chemically. I prefer growing in soil for ease but hydro for results.
It can be a problem with 90°angles apparently but my tent has 3 of them with 125mm ducting and an inline fan and I get by alright.
The major problem I had was with sucking the air through the hood because the smell escaped through tiny holes in the creases of the ducting. Now it's blowing...
To be honest, my favorite method was always hydro but there's no way I would have gotten my head around what to do without growing in soil first. Now days I only use soil and organic nutrients made from bird guano. No need to pH anything and the buds taste phenomenal without a need to flush. It...
I'm sorry to tell you this but I've used amended coco before and it was a total nightmare. I'd either get some pure coco eg in brick form - or soil from your garden center/hydro grow shop.
And please don't take this the wrong way but you sound like this is your first grow so I would highly...
Hello good people of MP. I'm a bit of a lost soul, hence the name, but I'd like to stick around here if you'll have me. I'm British but live in Spain. Love growing weed and occasionally get to smoke some when my wife passes the pipe over.