I’m wondering how to plan finances where we don’t feel strained financially between 50-60 and then be flush with more money than we need past age 60. How could I model this better?
FIRECalc can model this. Be prepared to spend some time learning the ins and outs of the program and run several scenarios.
Also take some time and try to get a better handle on your post-retirement expenses, especially as you intend to do extensive international travel. Not saying this will necessarily increase your expenses, but it is different that what you've been doing, so take that into account.
Run different scenarios at healthcare.gov (assuming you're not intending to get healthcare internationally; if you are, heavily research those options) to see how much you may pay in premiums, what your PTCs may be, and max OOP costs.
Go to socialsecurity.gov and plug in your expected future earnings numbers to get a better idea of SS benefits (assuming they won't be cut).
Finally, and somewhat controversially, read Die With Zero by Bill Perkins. Has a different perspective on spending. There's a 22-page (!) thread on this book: https://www.early-retirement.org/forums/f28/die-with-zero-book-109520-22.html