Would you attempt to blue or brown a gun part for a customer using a spray-on method?

The spray on bluing I found was on amazon and is made by Duracoat. Most of the spray on options I was looking at were very different then the bluing solution in the bottle that you would use on bare metal. After reading a few customer reviews on this product specifically, most loved the end result but compare it to more of an epoxy coating rather than a chemical reaction produced with the Perma Blue. I think I would talk to the customer about what they want the finished product to look like and that may help me decide how to achieve it. Of course, the decision may be a lot easier depending on the items that need bluing. If the customer wants a barrel or frame done and they like the glossy finish this Duracoat gives them, then that would be my solution but I don't think I would ever use such a solution on machine screws because it sounds like there is some build up that may result in the threading no longer working in the firearm and this would be really bad come time to reassemble the weapon system. Another reason I wouldn't use the Duracoat on machine screws is because the screw that gets too much of this solution in the head may prevent my bit from properly seating and the buildup may cause me to slip the bit and ruin the head of the screw. It may even be that some jobs require both Perma Blue on machine screws and the Duracoat on the frame as requested by the customer. Anyway you go about it please be sure that you follow directions and apply the solution correctly or you may be making a costly mistake with a client's gun. It's a lot more work to use the Perma Blue but I feel like the result is more aesthetically pleasing so if I had the choice, that would be it.