edited to correct mistake I made in location. SW of Theev is the better choice.
Well we can figure the minimum costs to ship a tank of anything, ice, water, Hydrogen to a location in deep space. The fuel cost is 10% of the total hull times the number of parsecs moved. A 1000 ton ship may get away with about 200 tons of space for operational needs leaving 800 tons of space for cargo and fuel.
Assuming a J2 to get to the middle of a gap. To use the Sindal sector a good location would be hex 2016 as Belisknar posted. This would allow Imperial shipping to leave Realgar, jump to Vume, then to the Fuel depot, then to Salif, to Number One and they are on the Florian Main.
To get from Vume to hex 2016 is going to cost 200 tons of fuel to get there, and 200 to get back. This leaves 400 tons of fuel that could be left there to fuel subsequent ships. This could be boosted by drop tanks but as a minimum shipping capacity 400 tons for a 1000 ton ship is what you can expect.
So the 400 tons of fuel have cost 400 tons of fuel to get there, plus mortgage, maintenance and pay on the ship to move it there. You can use unrefined fuel cost as a base, but it shows the customers better be willing to pay big money to fill their tanks.
The advantage of course for merchants in Realgar is to get to Number One port the old way took 13 jumps (Chalchiutlicue,Prime, Hradus, Hex, Imisaa, Fist, Lilgan, Exocet, Blue, Torpol, Oghma, Thebus, Number One.)
Vs the New Way
Realgar to Vume, Fuel Depot, Salif, Number One. 4 jumps saving 2 months of travel time and umpteen thousand credits in time and fuel. Even if the trading ships are force to Pay 3000 Credits a ton for refined fuel (why sell unrefined if you are the only gas station in the parsec.) it is still a savings.
I agree the various systems closest to the Fuel Hex may chip in and send ships to the Depot. Vume, Theev, Homestead and Salif all have gas giants or icy core planets or belts. Iceballs are possible.
A fueling station in 2016 would have the wealth of the Florian league passing through it to get to Imperial space faster. 2016 is better than my earlier post about hex 1915 because the 2016 hex allows 5 planets with gast giants and asteroid belts to supply the base as opposed to 4 systems at the 1915 location.