How many plants and what strain for 2x2 250w grow

Just wanted to get some opinions on what I should I have a grow box dimensions 2'h x 2'w x 4' tall I'm using a 250w mh light. I'm aiming for a ScrOG setup and was wondering how many plants should I try to fit?

Secondly what strains tend to be best for scrog setups? I've heard sativas are good due to their stretchy nature. Thanks for the advice

2 big ones

Thanks, any strain recommendations? Currently looking at barney farms lsd and vanilla kush.. Would like something with decent yeilds, low grow height, and an energetic high.