RE: Type of material for scratch building
i have used 3mm abs plastic plate for my superstructure of my jagdtiger with in the hooks square 3mm plastic profile reinforcements to strenghten it up all together bound by bison supergleu
it it very strong bounded will stand the big 128mm alu canon with alu strips mounted on the upperplate of the panzerjager
for the hull i would recommended 5mm plate with brass or ball bearings