Dad moves to new city - how do I keep custody arrangement fair?

Got an opportunity in Austin that I can't pass up. Currently have 50/50 with my kids (ages 8 and 11) in Dallas. My ex is NOT happy and is threatening to fight this in court. I don't want to lose time with my kids but I also need to provide better for them financially. Has anyone else done a long-distance custody situation? What did that look like? Do I have any shot of keeping it relatively balanced or am I looking at summer/holiday-only visits?