Hi Don,CBO
Well I should have checked this further, Tarriffs site has from memory (its currently down) 180 @ 81 (19) degrees, but interestingly this site
http://www.wwiivehicles.com/germany/...zkpfw-vi-b.asp
quotes amongst other thicknesses,
185@80° ie 20 degrees
with rounding up the latter figures give you a value of 20.
Best Regards Chuck.