Need help with adjusting paint for ghost stripes

[ILM MK3]

Okay, so I am pretty certain I am going with GM Ashen gray (GLJ) paint, and I want to add ghost stripes as well that are a bit darker. So, the question is how much to adjust the paint formula by to get it slightly darker? I just need a starting point for a small sample that I can spray out and compare with the base. Each 4oz sample is $20 so I would like to get it right in as few tries as possible.

The formula (non-cumulative) for a pint of the color is:

4530S Flop cntrl agnt 49.8g
805J Jet Black 34.1g
827J Blue 5.2g
886J Opaque red 1.7g
802J LS White 0.5g
1011S Fine satin wht pearl 2.3g
1001S Wht Pearl 1.7g
150k B/C balancer 232.0g
175k binder 103.6g

So do I add black or reduce the amount of another color or what? Just looking for a starting point and recommendations from those with experience.

I really like the shade difference in Howards car (Cobradvm). I always see people say just a touch of black added, well, what a touch? or at least a good starting point please.

Thanks!

[ILM MK3]

Also, I plan on doing 4 coats of base, how much paint is needed for that? Or how much is needed per coat (unreduced)?

Thanks again

[NHolds]

Definitely don't leave anything out.. that will effect the color. If it were me, I would just add black. As for how much, it really depends on how much darker you want... I would go an ounce at a time til I got the right shade.

[Presto51]

Another way to do ghost type of stripes, is go to the paint/color chip book find a color that is very close to your base coat color but darker, spray one or two coats instead of the standard three or four.

That way you don’t have to worry about repeatability on the changes that were made with your original paint color on the test panel to your car

[Derald Rice]

I ghosted in my sebring stripe. The base color is honda silverstone mica, and the stripes are ghosted in what appears to be the same range as CobraDVM's. When my stripe paint was adjusted, it was the same silverstone mica that was used for the base color, with 2 drops of black added to the paint cup. I know that 2 drops is not very accurate, but that is what was done. The drops were off the end of a standard paint stir stick and the paint cup was about 1/2 full. There are only 2 coats of stripe color on top of the base. It is just enough to provide a visual definition without being overpowering.