hey! I used to sell these guns as well as use them. I recommend the 1.3 tip for your base and the 1.4 tip for your clearcoat. As for the fluid caps, stick with the instructions and follow their recommendations. If I recall, 1.3,silver, 1.4, purple. Double check me though, it's been a couple of years since I dealt with these guns. At my age, sometimes breakfast is a blur!