I've been breaking my neck to customize WooCommerce using one of SiteOrigin's theme and builder. Starting out (this time) with WordPress 4.6 and moving through to 4.8, I found this to be a great tool to help figure out where to make changes.
I stopped using the Site Builder and just used this with the Customization CSS that's now part of WordPress 4.8. I'm using 'Orbisius Child Theme Creator' which is great. So, these are the best tools I've found for customizing themes and creating child themes, especially since there has been so, so many changes made to WordPress and the plugins I was using - its been a very long year, a lot of double and triple work...uuuggggggh.
If you want to create your own Child Theme, have a theme you've devoted a lot of time into developing, or need to adjust your current theme, THIS IS THE TOOL to assist you!