Is there a closet you could use ? Putting boxes under the plywood and then having to move the plywood to get to the boxes daily sounds like a lot of work plus when in the boxes you need to be sure air has the ability to flow through the box (not moving air) ... they may well mature at different times ... when the first buds look really done, stand back and look at all your plants and determine if it's just the tops or the majority of the plant ... if it's the majority of the plant cut the whole thing down and hang it upside down ... if it's just a 1/2 doz buds cut them off hang upside down in a box suspended from a wire ... growers seldom harvest late and new growers even less often ... I imagine you'd like to start the next grow but if you're not real careful w/ the harvest and cure of these plants then they may all go to waste and there looks to be a lot of good bud there so losing it would be a shame ...