The codom thing is a very rewarding way to get started, cuz at the end of the week when you want to see what your thousands and thousands of dollars has put in your racks its much more rewarding to hold a mojo or pastel or yellowbelly or whatever you get, than to see a whole bunch of normal looking snakes. The time and the money of this hobby is somewhat overwhelming and a visual reassurance of what your spending so much time on is always good.

As far as what you decide, as what has already been said get females first and males will be cheaper by the time the females are ready to breed and you will have months and months to think about what you want to breed them with and see how your opinions change over the next year or two.