Which school, if any, would be best for applying to a top 20 grad school?

[davewill]

I am trying to gauge how important work experience is to the acceptance rate. I'm assuming it is considerable, but I don't know if it means that it would be much harder for me to get in. I guess that is something I will have to figure out when I get there.

The best way is to think of your application as a package. All of the components have value. If you have a good school, the right degree, and great grades, then you might need very little work experience. If you have lots of good experience, a BALS plus a few MOOCs might do the trick. That's why I pointed you to the OMSCS online communities, you will see what different people had who did and didn't get in.

In your case, since you're already working in the field, I think that your time (not to mention money) would be better spent getting a CS degree quickly, and relying more on professional experience. In your shoes, I'd go ahead and apply as soon as you get the degree. If they don't accept you, then gather more professional experience and try again.