I agree with everyone else. Red is the first color to go away in low light. Green is the brightest to my eye, with yellow next. I'd have green for the 20. Yellow for the 30 and red for 40. You don't want to be shooting 40 yards in low light anyway, so it doesn't matter if you can't see the pin. Right?

If I were in your shoes, I'd go to the archery shop and see if there are straight replacement pins for that sight. If not, I'd buy another sight that lets ME choose what color pins go where.