Hello,
All of the above solutions will work.
However, I have some printable 'box tanks' (they are literally a rectangular prism with the picture of the tank) on my blog. Granted, they are not quite to size, but I think they should be close enough to act as proxies while you make up your mind.
If you're interested, my blog is here:
http://40000pirates.blogspot.com/
Good luck!