For Airbrush: use Mr.Aqueous Hobby Color Thinner: 1 paint: 1 Thinner.
For Handbrush: Can be thinned with water or used straight out of the pot.
Gloss can be adjusted by using H-40 Flat Base – mix approximately 5% of H-40 Flat Base to convert gloss colors to a matt finish, or 5 to 10% for a semi gloss finish.