Hi! Tnx. 
We use the OutMsg pattern for the most part, and here is the article we read before trying it out. http://folkertdev.nl/blog/elm-child-parent-communication/

OutMsg works really well, and is the best approach we have found :) But also make sure to checkout the official elm-guide. https://guide.elm-lang.org/reuse/

In most cases you should look to not use a nested component structure if possible. Cheers ! hope it helps.