fuel

I fully empty both tanks very fill or what's the point, you might as well save the weight and drive with an empty sub if your not going to use it.

Last week Safeway had a 30c lt off if you did your shop!! Happy days! I saved over $50 at the pump on that fill of 160lts!!

I have not ever fully filled any of my vehicles at the bowser, but the Patrol holding 125L, my wife might have a heart attack if fill it from empty. Might transfer the sub to the main when nearly out then hit the bowser. Keeps the sub tank fresh and happy wife happy life. I know it's the same amount of fuel and dollars at the end of the day, but might lessen the blow at the bowser.
How long does it take the sub to transfer?

my gu takes about 30 minuits to transfer a full sub tank to main tank .

Also tyre size makes a big difference as well as tyre style, Tyre pressures
ATM I get 12.8 /100 k running around town on 305 Mickey T MTZs
Towing I think I get 15/100k, Just doing a fuel run now to see what I return
with new intercooler fitted. Approx $220 to fill both tanks @ $1.45- $1.50