Hey fella, been a minute, but I have a few tips. Those stakes being jammed into the soil may do some root damage, so I would think about duct taping some PVC piping on the out side of the pots and use those to tie your plants up. They will be sturdier too. As for the root bound issue, you may see some, but IMO the soilless medium is able to provide better root growth, allowing a more efficient use of the roots so they grow different then when in soil. Bottom line, I wouldn't worry to much unless you start to see roots coming out the bottom of the pots at a rapid rate then at that point I would place some more 3 gal buckets under those with a 3 to 4 inch layer of the sunshine mix in them and the roots shooting out the bottom of the mane pots will start to create a new root structure in the new area.
Adieu