been working on this recently:
http://www.b26354.co.nz/EVA/
Found some spherical acrylic lampshades locally which were 300mm 400mm and 500mm diameter. 400mm seems to scale to about 1/5th scale although, in hindsight, the 300mm would have been a more manageable size (but an odd scale). 500mm would be about 1/4 scale which is just too big
http://www.b26354.co.nz/EVA/
Found some spherical acrylic lampshades locally which were 300mm 400mm and 500mm diameter. 400mm seems to scale to about 1/5th scale although, in hindsight, the 300mm would have been a more manageable size (but an odd scale). 500mm would be about 1/4 scale which is just too big