Newbie new grow help

I have a 90cm x 90 1.2m high indoor grow . I had four ten litre tubs under a 400w light in coco and air post .. All vented ect, setup is pro setup ... I had to lollipop my plants because it was such a small place the bottom was receiving little if no light.... So I was thinking is there away round this but not topping ! Or am I better to put 2 plants in a nft setup = plants get more light and more bud or 4 plants and risk the over crowding... Any advice or info greatful only my second grow so a newbie really

I am thinking of doing two plants now in nft hydro and topping and doing dog style to get even canopy and maybe upping to a 600 watt bulb.... Any advice is helpful
I have attached images

i grew to 1.5 feet and then switched to 12/12 I am now nearly 3 weeks in to flower
I have no idea what to expect at this stage so are my girls looking good ?
Thanks for any advice info ect

Your plant is gonna double in size so if you don't have the head space do research on super cropping or LST

It's not the height that's a problem it's how many plants to stick in a space metre square and 2 meters high ... And what height to veg till n what height to flower for best yield and coco or nft hydro