Here's my old rug colour Blue and Grey dyed over 1/8th yd of wool using Majic Carpet Dyes
1/256th tsp. Blue
1/512th tsp. Seal Brown
1/512th tsp. Black
This formula was dyed over 1/8th yd of natural wool using a Microwave Dye Bath as follows.
Add 6 cups of boiling water in a microwaveable safe vessel, I use an 8 cup measuring cup because it has a handle that does not heat up. I like to boil my water on the stove, it is a lot faster for me than using the microwave.
Wet wool in synthrapol or jet dry.
Add dyes to boiling water stir very well, add wool to water, stir for 1 minute.
Place in microwave for 2 minutes.
Remove, stir, add acid in the form of vinegar (1tbsp.) or citric acid, ( 1/32 tsp.)
Stir more, place back in the microwave for 1 minute, remove and stir, repeat until water is clear.
By all means use a conventional dye bath to create this color.
Using the chart below the Blue and Gray Formula for 1 yard of wool would look like this:
1/32 tsp. Blue
1/64 tsp. Seal Brown
1/64 tsp. Black