Fuel Tank Brackets

[Richard Coutts-Smith]

First post on the new set up, so here goes.
Was in the process of fitting left hand fuel tank brackets to my C60S, when I ran into a snag. While everything bolted on OK, I found that the tank was too small, or the brackets are too big!
They look as though they are for a tank 12 x 12 (inch) instead of the 12 x 10. Also noticeable was the pressed depressions at the back, below the chassis rail. This appears to line up with where the winch cable runs. So the question is, what are they off? I notice in my trusty MB-C1 that the Gun Tractor has a larger fuel capacity. Is this what they are off??
Confused, help appreciated.
Cheers