Well, I'm Marketing applicant, but with a background in Finance.
It seems you had a good coursework during undergrad and masters. You may have shot yourself in the foot, as you implied, if you got bad grades in important courses.
Of course 168Q is a great score. But since you are applying to Finance and aiming for top schools, schools probably can find several applicants with 170Q. So, if you think you can achieve 170Q if you retake the GRE, I recommend doing it.
Your work experience is interesting from a general perspective, but I don't think people will find it interesting for Finance PhD application. Of course you include that experience in your resume, but I don't think you should emphasize it in any way. Work experience in general is not so important for PhD, and even less if it's something not related to your studies.
Some schools give the applicants the opportunity to write a second letter of a more personal note (not the statement of purpose). In those cases, you might write more about that experience.
No teaching experience and it seems that very little research experience. If your research experience is just your thesis, then any applicant with a masters will also have it. Not a good way to show you're a top applicant.
And I really don't see a strong explanation about why a PhD. It still looks to me that, if given the opportunity, you'd go to industry instead of academia. Of course I know a lot of PhDs do that, but that's not what schools want to see in an application. When you say you want to help the next up and comers, it seems you're talking about teaching. Which is also another possibility for a PhD, but again, not what they usually want to see. Typically, they want to be convinced that you are commited to academic research, and need to understand why. "Love to settle" is also something that may suggest you are not willing to change, evolve, take risks, work hard, which are some values several schools hold dear.
You may notice that being mid 30's may not be as nontraditional as you expect. Several applicants here are in that range. If you are nontraditional in mid 30's, what would you call me, a 44-years old? Going back to school recently may work in your favor. At least, it did for me. During an interview, I was able to show that I was still sharp academically because I had recently concluded my masters with great results. If you had studied a long time ago, it might look worse.
You can apply to Chicago, but remember that the odds aren't great. You know you have weaknesses in you profile, and top schools get a lot of near perfect profiles. I can't say really say which rank would suit your profile, I hope other people can help you.
You could also check my blog (link below) to see if anything can help you.