Sounds good. I've used Sterilite waste baskets in a ~3 gallon size when I couldn't get proper size pots; that worked fine. Paint or light-proof tape for the translucent models; don't forget adequate drainage holes.

I'm always leery of leaving a humid pocket of dead air at the top of the pots. Bugs like that, esp. fungus gnats. If you're stuck using the 5 gal. pots, I'd put 3-5" of drainage material** in the bottom of the pot and keep the top of your rootball within an inch or so of the top of the pot--no more than necessary to accommodate your watering technique.

**(Semi-smooth river stones from Ace Hardware, ~$3 a big bag, work well. I got some near-hydro roots going into 'em last time. ) If your roots populate all the soil you can replace some of the stones with additional soil in the same container. Kind of a transplant in the same pot. I do it allatime. :thumbsup: