I think what you said is that even though hubby would be spending less time with his kids he would be better off financially and more able to support them.
I think that you'll need to go back to court and define visitation exactly. Such as Hubby will arrive at ex's home on Friday March 22 by 7pm and have the kids for their spring break vacation. He will return the children by 5pm on Sunday March 31st. This date is to include Easter with dad.
Dad will pick arrive at his ex's home on April XX at 7pm and return the children on April XX by 5pm. Dad will pick up his children on Friday May 31st at 7pm and return his children on Sunday August 11 at 5pm. and so forth.
If you are just a couple of hours away it will still be hard to go get them on Friday, take them to your home, spend any time with them doing stuff on Saturday because they'll be tired from being up so late the night before. Then turn around on Sunday and bring them back so they'll have enough time to calm down, bathe, then settle down to go to bed by a reasonable hour.
I think that with the new job he'll also be working extra hard to prove he was a good choice for them to hire. This will cut into the weekends. He has to decide how much time he wants to give to the new job and how much he wants to spend with the kids.
Since they are younger he might want to put off moving away. I would spend every day possible with the kids. Even if it's just to go to get an ice cream at McDonald's after work. She can't say no if he has joint custody. He has as much right to the kids as she does. She cannot tell him he can't come get them at any time actually. day or night.