You're welcome Teddy. Something that goes undermentioned when SEOs run very precise tests on specific page side changes is that they're typically doing them on completely brand new domains with non-sense words and phrases because of the chance that their manipulations might get the site blacklisted.There's no loss to them if that happens other than unanswered questions. If the site does survive for a bit maybe they'll learn a few new insights. This level of granular, on site testing isn't a practical method for legitimate, public facing sites.
When it comes to sites that serve a business function aside from testing possible granular ranking changes, you're going to be much better served by measuring your changes against your user interaction instead of your search engine rankings. In that vein, design and test for the users on your site, not the search engines. If your site is getting visits but none of your business goals are being met, go nuts on testing those factors. Split test, iterate, and improve things with the focus of better conversions. Dive deep into services like Optimizely and research by the likes of Conversion Rate Experts. Use focus groups and usability testing to see how the minutiae of your changes affects interaction. You can go as extreme as you want to in that regard.
Most importantly, the bulk of search engine ranking strength comes from external factors: the number and variety of sites linking to your site, the quality of sites linking to your site, the trust and high reputation of sites linking to your site, the semantic agreement of sites linking to your site, etc. These factors are going to have many times greater influence in your ranking than your onsite tweaks in most cases. If your site is functional and complies with Google's own guidelines (http://static.googleusercontent.com/media/www.google.com/en//webmasters/docs/search-engine-optimization-starter-guide.pdf) you've covered the bulk of what you need to do on site. Focus instead on off site factors.
The site: search function exists mostly to provide searchers the ability to find a piece of information on a given domain. For example, let's say a reporter wants to cite an NBA stat from NBA.com, they'd use "stat thing" site:nba.com as a search. For users, that's useful in searching specifics, and for Google that makes them look all the better at "categorizing the world's information." Cache demonstrates the amount of information Google has archived and how quickly it's available. Back in the day--story time--Google used to advertise how quickly and how broadly they indexed things. In fact, they still do! If you look at a search result you'll notice a light gray statistic at the very top that says something like, "About 125,000,000 results (0.50 seconds)" for a search about hot dogs for example. This is Google saying, "We're BIG and FAST." The precise details of your site are way down the list to Google's own story of being big and fast.
If you focus your efforts in off site optimization, linking with other reputable sites, and building your network you'll be way better served because you'll be getting referral traffic as well as lift in Google. Cheers!