Mirror Wills - Suitable ? If so, are these a simple template ? Any recommendations , is DIY possible etc.?

My wife and I are a team and based on what I have read mirror wills look like the best option. We have two kids, and simply want everything to go to each other first, when either of us goes, and then on to the kids 50/50 after that ? While the kids are still young, we have agreed on the same guardian - so as far as we can tell it’s identical - hence we fall into that mirror wills category ? Is that correct ? If so, are they straightforward to do, a template online , DIY ?