I have some in plant troughs, deeper than a window box type. Currently in greenhouse to ripen, and they can be fed along with tom's.
I've wondered about guttering as well, I would think they would need soil/compost replacing every year, but maybe worth it, pictures look good, rows of guttering on the side of the shed, lots of strawbs hanging down. (would weight of crop pull them out of trough?) Or you can get a deeper guttering. Copper tape round the shed should keep slugs off, netting from shed roof keeps birds Off? I think I've talked myself into it for next year :- ).
I have shelf on brackets on an outside wall, lots of potted plants, i do sometimes find slugs there, but not often