There really is no absolute "best" setup... Personal playing style will cause some traits and charactersitics to be more valuable to one person than they are to another...
If you want my personal view, you can see it here:
Maintenece reduction helps you a lot, so you probally would want to get 20 mainence reduction to get only 5% maintence costs. It multiplies the ships you can support by 5, and thats a whole lot of ships : ) In mods though, this probally won't work.