I'm currently working on setting up a sub-theme from a theme that uses the Foundation framework. This parent theme has all it's CSS broken out into Sass partials with a settings.scss file that sets colors, fonts, etc. 

For the most part, the site that uses this sub-theme will need to look and feel exactly like the parent theme. However, I do need to override some of values set in the settings file.

How can I manage these setting overrides in my sub-theme in a way that doesn't make a lot of overhead moving forward? I could search my sass directory for all instances of various color variables and write a stylesheet that targets those areas but this seems like a lot of work moving forward — especially one multiple sites are using this parent theme. 

Any other advice on implementing a sub-theme off of an existing parent theme would be much appreciated, too.