My advice is for multiple, thin coats, This may require two or three for some colors, but for reds as many as five. I recognize this is frustrating -- because it is. But it helps with the solidity of color and without muddying details. Reaper has a paint with a lot of pigment in it that helps with base coating, which is worth looking at.
If you invest in an airbrush, it makes life so, so, so much easier. You can get to painting the details in a fraction of the time. Although, the cost of the airbrush and compressor is a serious factor to consider.