I've got the T230, great van.
If my memory serves me correctly, you may have a job fitting in the 600ltr upright if you want it across the bulkhead. I've got the 500ltr upright there,which fits snugly against the bulkhead,leaving me decent room to fit my other equipment in the back all neat and tidy. 500ltr should see you through a good day on the glass.
Yeah, 1ltr of water is 1kg ( more or less).