Adrian,
I grew Tetsukabuto also this year with Lofthouse buttercup and the G2 descendents of Autumn's choice F1.
I've grown Joseph's Maximoss before and it produced but I think it wasn't great but then some portions of my squash patch tend to get ignored. I still have some seed I saved and I kind of let it cross freely with the Maxima grex so some genes could be floating around.
I have a lot of space though so what I will probably do is plant the remaining Maximoss seed. All or at least a great deal of the new Tetsukabuto seed. Then also will plant G3 of Autumn's choice descendants and probably some lofthouse buttercup just for eating unless I find a place to isolate the latter.