Cecil,
Take a look at this Webpage:
http://www.wvu.edu/%7Eagexten/sustan...c/Moreon63.pdf
Scroll down to diagram #1.
Look at what West Virginia University did when creating West Virginia '63.
Notice that in several instances they backcrossed the F1 with one of its parents to accentuate certain attributes or crossed the F1 out with another variety to incorporate other attributes.
Then they kept track as shown in the geneology chart.
As to your other question, I think that when you cross an OP with a hybrid, you are crossing the heterozygeous gene grouping of the hybrid (obtained from both parents of the hybrid) with the more homozygeous gene grouping of the OP, and that you end up with a new batch of heterozygeous gene pairs many of which may be the same or similar to the gene pairs in the hybrid ... maybe not ... but then Keith could better explain that 'cause I'm totally out of my league responding to such a question.
PV