Probably the closest approximation I could do:
Would that work reasonably well, or the potential of the magnets is 'wasted' due to the coils not really being optimally covered/filling out the space?
EDIT:
So I worked around a bit, and figured to try and design a curved coil design.
The plan is the make a mold with the shape of the curved core.
Print the mold out of resin on my 3D printer, then mix epoxy and magnetite to cast the iron core.
Winding the coil around it might be a challenge, but I'll try make the mold as accommodating as possible.
Should probably use hot glue to temporarily stick 2 flat sheets on both ends to make the winding easier, and still be able to break those supports off when the coil is wound.