That looks really good, if you want to make your own, You could use a ~24" X 2" pipe with end caps instead of the big piece tubing I used and just drill and tap the bottom cap for drain, low in pipe for the pickup and 3 holes in the top cap, one for fuel in, one for fuel return, one for vent/return to tank.
When it comes to filling the tube, there are 2 themes, first is to use a low pressure pump running all the time, the other is to sense the fuel level and switch the pump on and off as the fuel level in the tube rises and falls, that's what I have. If you use something like a mr.gasket pump and let it run all the time, the fuel keeps getting recirculated back to the main tank, which may be good depending on how much heat is added to the fuel as it goes through the main pump several times, just a thought. Another thought is that once the surge tank is full and capped off, the main pump should suck fuel into it and you would only need the aux pump to bleed any air out.
Kinarfi
One more thought, as time goes on, water vapor turns to water and will accumulate in the tank, I made sure mine had a drain at the lowest point so I could flush water, dirt, etc. and if I need a bit of gas to wash a part or to build a fire while out, I have an easy access point to my fuel.
Started looking for my write up on my surge tank, couldn't find, but here's some photos of the build.
first of several