Any benefit to going from 11L to 15L pots?

Just remember, with your plants down deep in the pots, they will receive a lot less (reflected) light which will slow growth, especially with the bottom/lower branches. You could also trim the larger pots or maybe fold the sides down, so that the plants weren't "hidden" behind the walls of the pots. Also remember - more room for roots = more growth above ground and more substrate also lessens the chance of nutrient salts building up in your pots. Hope this helps,........ Organoman.