How to change default SASS number precision using Ember-CLI

I am using the latest version of Ember-CLI (1.13.8) along with the prescribed ember-cli-compass-compiler. When the compass/sass compiler does its magic, by default it rounds numbers to a precision of 5 digits. This causes problems with button alignment in Bootstrap, which has sizes specified with 9 digits of precision. I've managed to get this to work with two hacks, neither which I am happy with:

1. Override .btn{line-height: 1.428571429} in app.scss
2. Modify number.rb in the SASS GEM source code.

Both of these result in the value working, but I hate having to modify ruby source, and I hate overriding the .btn line-height because I don't know what other heights will be screwed up.

Using the new ember-cli and ember-cli-build.js file, is there a way to override the number precision at compile time instead of hard coding it the way I'm doing it?

Thanks