Hey Mahoney,
Best tool for this is
http://www.adultseotools.com/VWO
I've used a few tools for conversion rate optimization over the years and this one is hands down the best, especially for adult.
It can run multiple versions of the same page simultaneously to give you live stats on which one, and even which components of each, perform best on your traffic. You can create A/B tests, A/B/C tests and even advanced multivariate tests to help you fine-tune every aspect of your site to maximize traffic flow and conversions.
And once you have your pages tuned to perform as good as they can on your traffic you can then segment your traffic so that specific sources see specific pages. This means you can direct your ad buy traffic to pages that are tuned to convert best for them, which is often different from what converts best for affiliate traffic, search traffic or type-in traffic.
Conversion Rate Optimization has always been big in mainstream, but for some reason has never caught on much in adult.. not sure why. Testing page variations against a control, on live traffic, is the only way to get reliable results from testing.