Praecox Rainbow sex ratio (w/ 5-7 total): all males, all females, or what mix?

Akeath

I'd like some advice from people who have kept them on what the sex ratio for Praecox Rainbows should be, I'm planning on getting 5 at the minimum and 7 at the maximum. If there is something wrong with the total number please tell me. Oh, and I understand that males typically have red fins and females have yellow/orange, is this an accurate and good way to sex them or is there a better way?
Thank you for reading, and thank you in advance for any advice!

Fishin Pole

i have 6 of them in with some of my angels............I choose to go with 2 males to 4 females..........in general, for rainbows, the males are usually more colorful than the females........