I hate to be the party pooper but you picked about the worst strain possible to grow with a 400 watt light. Barneys pineapple chunk (or tangerine dream for that matter, I'm pretty much done with anything from barney that contains sativa) is an enormous plant and takes forever to finish and buds are generally sorta airy even with 2000W . I doubt you could sufficiently grow one PC with a 400 watter never mind several of them.
My advice to you is either a) possibly use SCROG b)to start over with a reasonable strain or c) Train the crap out of them or d)at the very least put them in flower earlier that you would normally put them in. They grow HUGE(this is not a good thing).
My advice to you is either a) possibly use SCROG b)to start over with a reasonable strain or c) Train the crap out of them or d)at the very least put them in flower earlier that you would normally put them in. They grow HUGE(this is not a good thing).