Stripping all the chrome. One of the single most important steps in saving money on a paint job is to strip your Mustang as much as possible yourself. This means taking off anything and everything that won't be painted. The more you take off the less the painter has to mask around. Masking not only takes their time (which costs you money) but it also results in areas that simply can't get a full coat of paint. If you take everything off, then the painters can simply scuff and spray, which will give you better and more consistent coverage.
Paste and powder paints should be mixed in quantities sufficient for immediate use only, as these materials often become unfit for application if allowed to stand for three or more hours.
Like this, it will actually take quite a while to reach a number that is close enough to the yellow color you've chosen that you can't tell any difference (and mathematically, you will never actually reach an average of 4!)
If you decide to do your own body work discuss it with the paint shop first. They'll probably have recommendations on the type of primer you use. Some brands will be more compatible with their primers or color coats. The rule of thumb is to stay within the same brand of paint, both for prep and color. Even the cheapest paint shops typically use a brand name on their intermediate and higher paint jobs. Find out what it is and use the same brand as your primer coat. This will ensure you don't create adhesion problems for yourself down the road.
Before you start painting, it is a good idea to keep an eye on the weather for rain or snow. You don't want to start painting only to stop abruptly because of the weather.
To balance color, you must grasp the interconnectedness of color schemes. All color interactions are defined in the color wheel, and it has been used to build color schemes for centuries.
By far, the most important characteristic in determining whether you are Warm or Cool is your hair color. If you can't determine your exact eye or skin tone, then your hair color will provide the answer. Why? It frames your face!