WCAG: Can I just link users to a high-contrast mode tool?

I'm on a project that needs to comply with Section 508 and WCAG 2.0, and we are going to support all the accessibility tags and everything just fine, but then I hit a snag with color contrasts... Trying to make all colors have enough contrast both with the text and background colors (to follow WCAG) as well as contrast compared to nearby items, I'm having difficulty finding the right colors without completely changing our color scheme.

My manager suggested we could just link to a high-contrast extension in Chrome or provide instructions on how to enable high-contrast in Windows and don't worry about meeting those requirements by default (all our users will be on Chrome in Windows).

I'm wondering if just instructing a user that needs a high-contrast mode, how they can enable it via external tools, is acceptable within WCAG 2.0.

Another option at the very least which I'm fairly sure must be okay, is to enable a toggle on our site for a high-contrast stylesheet that they can toggle on, still leaving the default mode that doesn't follow the rule.

Update:

After further research into this after posting this question, I can't find anywhere that mentions being able to use a third-party tool to avoid having to create a high-contrast version ourselves, which leads me to believe that this probably isn't allowed then.

The research along with @unor's response does tell me that I can provide a high-contrast mode that the user can enable, allowing the main version to remain as-is. As long as it is easily accessible by the user to toggle.

Thanks.