Based on memory--Many years ago (in the 80's,) when I first began my research program, many of the hybridizers (collectively) said there were two things I should remember.
1) I should use the better cultivar (of the two) as the pod parent, as the pod parent transferred more traits.
2) Like breeds like.
I've been reading The World of Irises again. At the bottom of the first page on genetics, it states, "Just remember that like breeds like." I'm sure I read it before.
Here is a good example of "like breeds like." (see iris-photo for pictures)
Pod parent is 1810-06variegata. Rebloom siblings but not this one.
Pollen parent is 1620-09-Rebloom breeding but not this one.
resulting children=2110-clump (The brightest one will go on Halloween Treasure)
Just thought this was an interesting example.