Not sure exactly what you're angling for, but at Delta you would be able to hold at least 15 days off/month pretty easily once you get off of reserve. You can work more if you want, but within a few months on most NB's you should be able to hold a line. It's all personal preference after that.

We don't have straight week on, week off schedules like Netjets, but with minimal seniority and proper bidding you should be able to put together a schedule that closely resembles what you seem to be looking for.

That said, I'd say the cart might be before the horse. Any of the majors will provide similar scheduling options. Get your interviews ASAP and then pick based on what you're offered vs QOL/basing etc.