I'm about to give you more ways to mess with your plant, so if you're really trying to leave it alone, don't read. *grin*

1) Although your cropping & roots are the major cause of stalled flowering, here's some food for thought on humidity:

I'm on my first hydro grow, and I, like you, have not invested in any humidity-measuring equipment yet. But early in flower, I noticed that flowering had stalled, and thought my humidity might be too low. I raised it, and the plant exploded with buds overnight. So you might try boosting your humidity.

No need to invest in anything hefty to do it... The first time I just put a layer of hydroton in a shallow Rubbermaid-like lid (about 1' x 2'), put it in the grow closet, and watered this "pebble tray" regularly. Then I hung a damp towel behind my fan & kept that damp, too.

Now I've kicked it up a notch: I've got one of those steam cleaner things that looks like a teakettle with a hose on the spout, and I use that to give the whole grow closet a blast of steam every couple of days. A drug-store vaporizer (like your mom used to put in your room when you were sick as a kid) is another good option, and you can get one for under $10. Just remember to run a fan at night after humidity blasts to help keep your buds from getting moldy in the dark hours.

2) As for your roots, I've not had that problem as I have one plant in a 10 gal tub, but have dealt with it in soil applications. If you can bear adding even more time till harvest, you can correct the rootbound sitch now, which will likely help growth.

Wet your fingers in rez solution, and then tease apart your clump of roots as best you can. Some will break, and that's what will stall your growth again, but once it recovers it will grow much more vigorously. (Besides, after cropping, you really have more roots than your plant needs to support the green growth it has.) Keep the roots under water while you're doing it, else your plant will probably wilt drastically. Then add 3% hydrogen peroxide to your rez, about a tsp per gallon, every 24 hours for a couple of days. This will help the roots that are still stiffled in the tangle to get the oxygen they need, and it will help prevent root rot by killing off any slimy stuff.

And if your rez temp feels vaguely warm, throw a few ice cubes in a few times a day. Roots like it cold, and the stuff that rots them doesn't.

Or just ignore everything I've said. As I mentioned, it's my first hydro grow. *wink*