Launch Watir/Selenium Chrome driver binary from an arbitrary location

I want to use Watir to start a chrome for an older version of chrome, say /Application/Google Chrome 30.app

Here's a ref link saying chromedriver expects Chrome install at specific location:

Mac /Applications/Google\ Chrome.app/Contents/MacOS/Google\ Chrome

Here's a ref link for setting up Chrome executable in a non-standard location

ChromeOptions options = new ChromeOptions();
options.setBinary("/path/to/other/chrome/binary");

How can I do that using Watir, given syntax like

driver = Watir::Browser.new :chrome

Thanks!