Just an update - Rowan after a couple of weeks figured out how to get as much of the forage as he wanted out of the muck bucket setups, by taking a giant mouthful of forage + net, dragging it over the side of the bucket, and shaking it so all the forage fell out onto the floor, and Hoovering it up. He's no dummy!
So yesterday I moved it into a 3/4" net hung from the middle of his shed so he can't press it against the wall and get big mouthfuls out. I'll check on him tomorrow and weigh to see how much he ate in two days, but my friend poked her head in there today and said he doesn't look sad or frustrated, but is definitely very busy poking the swinging net with his nose and then picking up the tiny rain of bits that fall down. I also ordered a 1.25" net that I will try double-netting with the 3/4" and placing in the corner, to see which setup he eats faster out of.
So if anyone is interested in a couple of muck bucket toppers...
I think next spring I may also buy a string trimmer to really punish the grass around the edges of his track - I think he gets quite a bit eating along the fencelines and given the crestyness and possible foot tenderness he had this year I just don't want to risk more serious issues.