I think Halinski's armour models would come close to perfect fit. GPM and Modelik
are good but there always seems to be a few fit problems.
It isn't always the designer but also the production process. As in how many rounds of beta building does the publisher go through to get the last bugs out of the product.
1/6 scale ! - you must have a lot of space to work in. A Kingtiger model about 170 cm long - inpressive.
Regards,
Charlie