There is a self-blue (lavender) thread and a porcelain thread. Both might be helpful to you. Let me know if you want the links and I'll track them down for you.
Links would be very much appreciated. I will try to hunt the topics down myself after work. If I can't find them, I'll come asking for help!

Most breeders prefer to keep blue and lav genes separate rather than one bird carrying both.
agreed. If you decided to outbreed lavender do so with Black not blue. anytime you get 'splits' (lavender to black) the black offspring you can't visibly tell if they will produce lavender or not, so it can be a bit difficult with a breeding program.
What does the split lavender mean exactly? Other than a lavender bred to a black?