However, a high paying 4 day may go junior if the base is mostly commuters. It's hard to make a pairing like that commutable. And often times guys that live in base avoid 4 days for 2 days back to back or day trips.

Also, not all lines are pure with high block trips. If it's a typical 4 on 3 off line, there is going to have to be a lower block trips there somewhere. You also would run into 30/7 issues unless you had 4 days off between trips as well. And then the problem is is that the lines days off may not be constistant anymore. In other words, if you want high block 4 day trips AND all weekends off, it's tough to build.