Hi,
i have a short piece of hose with a tap on one end , the other end connects to van tank,
i simply park up pop the back pack on the ground, open the side door, pop the end of the hose into the back pack, turn the tap on and it fills up whilst i get the pole set up, then sometimes i refill it the same way at the end of a job whilst packing away so its ready for the next job,
but that works only when i have an odd job on each street, otherwise i pop the hose into a 25ltre container as i do the fronts etc, so in that respect your tap would be ideal.
Gary.