It seams to me your problem is filling the tanks in a public place, not how you store the fuel. Nobody would know if you had drums of gasoline. As long as there are no ignition sources your alright.
The boat and car issue is how the gas is dispenced versus a tank. Boat bilge’s also require a blower to remove flamable vapors. Cars and boats have contained fuel lines. No open contaners or transfer of fuel. Using a tank and pump vapor is pushed out of the container being filled. The movement of fuel in the hose can create static, hense the grounding issue. Plus sometimes someone may have a charge from their clothing.