Am a renault fan mate,
I used kangoo van before the trafic and used a 350 L tank, am not all wfp so this done me each day, weight wise it prob would of taken another 150 L so 500 L tank easy, so if your staying on your own think this sized van, ( kangoo berlingo partner connect type van ) big difference in fuel going upto to trafic van but more suited to my needs and use a 650 L tank now, working with pump flat out and not moving the van I can empty this in just over 4 1/2 hours if am not connected up filling as I work.
Nothing flash about my system mate, it's all diy and most bits were bought of eBay.