Very interesting. Thanks for sharing. I haven't looked at the pointed site yet but will do once I get some time on my hands. Maps end up nerd-sniping me.
The offset also forces the gore to be bent in two directions, so it’s also bit tricky, and makes the gore stiffer then it needs to be, dampening the paper there certainly helps.
I made a custom projection once, that's a bit friendlier to fold and comes in one tile.
Has no rendered flaps, but you should get the idea where to place them.
Still somewhat stiff, but managed to actually build two of them, would recommend printing on heavy A3 sheets or bigger.
Anyone is welcome to iterate. There even is a todo list with obvious things to improve upon.