The main reason I bought the pump was the ease of filling the tractor.
My tractor has the tank on the back behind the seat so it was difficult especially for my wife to stand on the three point hitch and hold the 5 gal. canister for 5 minutes.
1*My diesel consumption isn't too high.
2*In the near future I plan to install a hook on the 50 gal drum and use my FEL to load it on a trailer and take it to a local COOP to get agri diesel.
3*I buy two 5 gal containers anytime the level in the barrel goes to about one quarter and pour them in.
1*Last summer my usage was about 10 to 12 gallons a month.
That worked out well with my 30 and 55 gallon dual drum system.
I could have used a 30 and 30 gallon drum combination or a 15 and 30 gallon drum combination or a 15 and 15 gallon drum combo depending on how much under 10 or 12 gallon a month I figured I'd use.
2* How would you attach the hook to a plastic drum.?
Why would you need a FEL to load the drum on your trailer?
An empty drum is not that heavy; or are you talking about taking it to get it filled when it is still about a fourth full?
3*Why not get a 15 gallon plastic or steel drum and take it to get filled and use your pump when you get back to pump the fuel out of it into the larger drum ?
Probably could even get agri / off road fuel by using the 15 gallon drum.
You could also take 2 or 3 5 gallon cans and empty them with the pump instead.
Either way it eliminates handling and pouring from those 5 gallon cans.
This is how I would be replenishing the fuel in the 50 gallon drum if I were in your situation especially since you already have the electric pump.
You are already using the pump to pump fuel out of the 50 gallon drum so nothing says you can't use it to pump fuel out of whatever you get the fuel in.
L B 
