Also, quick question; I've noticed a lot of people using tanks, what size are they aboutish? As they would have to be a bit larger to support the steam engines and boilers required to power them.

I'd say this size ratio would be acceptable for tanks

[url=http://fc07.deviantart.net/fs71/i/2011/105/f/e/steampunk_tank_by_winterstalker-d3e2ijy.jpg]