I, too, often think I've got more room for a grow than is feasible!
Other than suggesting another tent for one or two of them (or a closet you can convert), I would suggest doing some defoliation so the light can penetrate below ... do this slowly as this may stress the plants so do a little today and see how they react, then do some more if they're fine tomorrow, etc. This is probably going to be pretty important to do if only to get more air flow through everything!
You might also consider harvesting them in stages even after doing the defoliation as the whole plant is not likely to mature at one time... the tops first, then let the lower bud sites have another week (maybe longer) before they're harvested (and you might enjoy not having ALL of them to trim up at one time!). The only problem with that approach is that you probably shouldn't do a flush as this would negatively impact the lower bud growth but as you're growing with organic nutes, it really ISN'T a problem!
Good luck - it's a beautiful grow.