>>5994157Depends on how many different ethnic and variations you need to make for your working environment. 1x male and 1x female would be relatively straight forward since you can rely on traditional ideal features.
10x of each would be hard. The character designer, Shigenori Soejima talks about this in the Persona 4 design works.
For me its probably men since there's lots of material on how to create different female ideal types (cute, sexy, milfy, etc). For men not much exists.
Take a look at Free! if you want an idea of how little minute differences on multiple men supposed to be idealized pretty boys add up.