How to obtain a red facor sun conure???

[Hasnainraza]

I am looking ro breed a red factor sun conure identical to the one in the second image (myko's aviary phillipines), The one towards the right in the first image is obtainable but the female I have is just yellow or natural. I have heard that breed red into red will get you darker red and that red into yellow will give you variation. What should I fo for with my options?
TIA