Grow log from a while back I did the same thing https://www.dmt-nexus.me...aspx?g=posts&t=21223
They like heat, humidity (mist daily), humic acid, acidic soil, and sunlight. Mine knew exactly where to crawl to get to the window and exploded. Grew very fast, over 10 ft. in a season. Give it a shot.

I wish I still had my plant, I went out of town and my wife couldn't care for it and it died... but while it lasted (4 years) it grew very well in the window.

No pics of the whole vine,
just one I took of the underside of the leaf and its nectar secretion.
http://i.imgur.com/jdK23h.jpg
Stuff was sweet to the taste.
It was wicked when it completely covered the window and created photosynthetic harmala blinds that rained caapi leaves down on my bed while I slept... It was the first and last thing I saw every day. Good luck.

If you watch closely you can literally see it spiral as it grows.
As for being root bound... That's what 55 gallon drums are for.
Oh yeah and don't forget to use molasses. Keep the soil soaked at all times in pots.
Use diatomic earth applied to the top soil to deter fungus gnats.
Check undersides of leaves for pests and spray with organic pesticides depending on the type of bug.