Probably,a combination of both,Steve..But I will be leaning towards square as much as possible..The B pillars have to be minimum 38mm o/d x min.3mm wall,and the rails above the doors,25mmx25mm,3mm wall..The rest is by virtual commonsense,or as the certifier sees it..The floor will be glass,with a reinforcer from B pillar to B pillar,plus,we need a fixed bulkhead between the trunk area and passenger compartment..I have to build a body,chop it,set it up on a chassis,and start from there,as I intend to do a new set of molds,with a 2''or 2 1/2 ''chop..