The only reason some of us, myself included, suggest adding water to dilute the HCl is to increase the volume of the solution. And increasing the volume of the solution may make your process work better for you. The trade off for diluting your HCl is it will work slower. Full strength HCl works best but then there are times when 1 gallon of HCl isn't enough to cover all the material you want to remove solder from.
It's your call.
It's your call.