21 Mercury R Pedals n Tank

Hi Everyone.
My driver is about 5’ maybe 5’1…82lbs w gear on. Skinny kid. I have his pedals on the kart w the otk extensions that have the pedals closer to the driver. The stock location they are too far for him to reach. His knees are a little lower than the top of the tank they way i have him now. Im trying to get his legs a little more straight but the tank (8.5ltr) is wide and his feet end up landing angled on the pedals when i move them more towards the front of the kart. I tried to find a smaller tank but can only find a 3 ltr. Is there nothing in between? Hes at this odd size where hes too small for stock locations and a but too tall for where inhave him now. I considered moving the seat forward, but then hes too close to the steeri g wheel and has trouble seeing over the nose. Just looking for suggestions and im sorry for the long description.

Ayrton Senna used a gallon antifreeze bottle as a fuel tank, duct-taped to the column supports, with a fuel line running down through the handle side.

I suffer from I a similar problem

I’d suggest just go smaller fuel tank. It’s what i’ve done and is the easiest fix. There isn’t really a need for 8.5 litres of fuel.