From bag seed? Plant as many seeds as you can let veg at one time. Cut clones from all of the plants that turn out to be female. Veg the clones for a while, then flower them. During that time, maintain the donor plants.
Monitor all of the clones growing traits and behaviours. Test the product of the clones when they're done in flower.
Pick out the best one or two from the bunch, and trace it back to the original donor plant. There's your mother plants. Put all the rest of the potential mothers in flower and be done with them.
In essence, the only way to find a good mother is by watching it grow, paying attention to all of the details, and testing the final product (through its clones).
