By common 12 volt transfer pumps are you talking about an electric frame mounted type of fuel pump, or are you talking the type that sits in the back of a construction truck used to filling equipment daily.
I would think to do what you are wanting to do, you are talking about a serious investment. Just look at the common gas buddy. Nothing more than a tank, hose and barrel pump, and they are hundreds of dollars.
Having said that I use a holley frame mounted type pump. I transfer fuel into some 15 gallon plastic drums, when I need to do fuel pumps and such.
I am not sure you will ever eliminate the spark of connecting it. I suppose out the somewhere is a switch that is explosion proof that you could hook up to it. To be honest I am not even sure the pump it self is explosion proof of fuel vapors around it.
On mine I have leads that are long enough to reach out one of the doors. I have just a lighter adapter wired to the end and use my jump box for power.
The vapors are what you need to be concerned with. Get the power source and the switch out of that area. So many variables there. An airplane hanger is much different than my garage at home. When doing any fuel work, I crack the overhead door a little just for vapors to escape.
Remember most vapors collect on the ground. I would really look around at other ignition sources, and be alert to them. You can do everything right on your end, and it all becomes a problem because the hot water heater is sitting on the floor in the corner.
It is all about the surroundings and not so much about the job. You have to be prepared with both, or neither will work. Just think about the common sense side, and ask yourself if this is a good idea.
Much of what I said pertains to fuel in automotive type applications. Not sure about the fuels you are talking about, but I would venture there is not much difference.
