Whatever variables you test, test them one by one. NOT all of them at the same time. If you test all variables at the same time, it would be difficult for you to follow the outcome as you don't know which variable brought your required action.

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Peace

Jay

Google Optimizer can do multi-variate testing, but it uses Javascript to create the options and that makes the pages bulky and slow-loading if you have many variables to test.

We developed an in house php script to accomplish the same thing on the fly and then send the results to the Google Optimizer interface so we can still allow our clients to easily access stats without having to worry about creating "heavy" pages.

I would be happy to give you the script, though you would have to install it yourself. If that's beyond you I can give you a price on having our person do it for you.