I am building a replacement set of wings for my old Passer Thermo.
I used some yellow XPS foam from Bunnings here in NSW Australia. It cut extremely nicely using my gravity hot wire cutter.
I'll attach a .pdf document. Unfortunately, the dimensions did not come out in the file transfer from the .dxf file.
Each side is a two panel wing. The first panel is 600mm long. 200mm chord at the root and 160 mm at the break. The end panel is 300mm long with a tip chord of 120mm. The TE is straight like the original. Technically a swept back wing.

Video of the hot wire cutting of the wing cores here:

Cutting wing cores. (1 min 33 sec)