As I understand things in Indiana, the 18-year-old's wishes will pretty much dictate where he ends up. That is with his mom, though he will be off at college before the custody evaluation and divorce is final.
The 14-year-old's wishes will not be honored absolutely, and I have asked for full legal custody as well as physical custody, with liberal "parenting time" (what used to be called "visitation") spent with his mother.
He is a kid who would not do well bouncing between houses on a weekly basis. He has already had the choice, and he has chosen to stay with me...so we have six months of experience already with me as his primary custodian.
His grades did not suffer (as his brother's did), he has not complained to me, he seems to be relatively happy (as happy as a kid whose parents are divorcing CAN be), and he eats pretty well. He "minds well" (as my grandmother would have said

), he keeps up with his household responsibilities, and I'm starting to teach him to cook and to do laundry. Most of all, we enjoy each other's company, and respect each other's solitude and silence. (Relatively easy given the similarities in our personalities.)
I am really lucky to have such a good kid, and I treasure each day with him. (Yeah, I know, every proud parent says that.) He has been the light of my life for many years now, a fact probably not lost on his mother. But she's the one who gave up the job.
As long as I don't come off like a smug a** to the custody evaluators when I point all this out, I think things will be okay. That's always the wild card with me...my confidence and directness sometimes come off to authority figures as a challenge or as cockiness.
Chris.