Just perusing the United contract, here is what I saw:

Basic scope says no more than 130 76 seaters until 1/1/16 when it goes up to 153. If United adds new small narrowbodies to their own fleet then the max # of 76 seaters goes up to 223, but on a 1 76 seater to 1.25 small narrowbody ratio. Also, to go above 153 76 seaters, United needs to remove 50 seaters on a sliding ratio of 3ish 50 seaters to 1 76 seater up to 5ish 50 seaters per 76 seater, depending on the total 50 seat fleet count.

Basically, no more than 130 76 seaters right now until 1/1/16. SKW is getting 40, Mesa 30 and RAH 50. So it looks like we're sitting right at 120 when they all get online. The total number of 70+76 seaters is also limited and figures into the equation. Not sure how many 70s there are in the Express fleet right now. Didn't look into it.

It looks like the RAH 175s are slated for delivery from July 2015 into the summer of 2017, so by the time they are all operational, scope will have relaxed to the 153+ range.