Sky West may be close to upgrading off the street, but if you could go to Go Jets and upgrade in 6 months, does it mean that you should? If you're flying a jet for the first time and "legally" qualify for upgrade, should you? After 6 months or a year on an airplane, does that mean that you are ready to sign the release and take COMPLETE responsibility for that airplane and the 53 (or more) people that aere on board that airplane? Have you seen all 4 seasons and would you know what to expect. Say you got on the line in March, and had the opportunity to upgrade in November. Would you feel comfortable deicing having never done it? What about hold over times? Have you experienced an emergency yet? In the first year, you should be focused on becoming a good first officer and learning the airplane. Your second year, you need to be working on your decision making that will be needed once you upgrade.
My point is, don't make your decision on where to go based on upgrade times. Just because you might be able to upgrade fast, doesn't mean that you should go there just because of that....