You will use more female fan pins than male because male fan pins are generally only used for extending a fan cable. If you plan on customizing every fan cable to length you are going to use a lot of female fan pins. I would purchase 3 pins or 4 pins per fan depending if the fans are PWM and you need to add extra for sensor connections for pumps, also if you want to run lighting via fan headers, etc.
I have been building custom cables for many years and I have used all of the products that are on the market. These are the best pins I have ever used. They are gold plated for high conductivity. They crimp cleanly and easily. They are difficult to bend and deform, they are a strong pin compared to many others. They are a great pin to work with, they save time and improve the quality of your cables.