Forget the quantity, stop and think logically, are you always moving forward and breaking or do you drive sideways all the time.
No forward baffles also affects your braking ability.
Do your own tests with an open bucket of water, first of all baffle it your way of thinking and then baffle it the correct way, see how much water you loose from both tests.
I drove a tanker with a mere 3,000 ltrs and the baffles still went the same way as a larger tanker, in the yard we had a 1,000ltr tanker
And guess which way the baffles went.
Instead of taking my word for it, ask your insurance company, or phone up a tank manufacturer and ask them.