No, you just looked outside the box. There are all kinds of marvelous things out there.

It ocurred to me, and probably to you, that it would be a convenience to be able to keep amidol in a glycol solution and the rest in water, mixing just enough at a time to do a sheet of film or paper in a tube.

The amount of sulfite may give some control over the color. You may not need the citric acid. Anyway, you have enough variables to keep you busy for a while.