Comment on WordPress SEO by SEO Dave.
Some SEOs believe its very important, one of those SEO factors I’ve not tested and went with the “better to be safe than sorry option” since it won’t cause harm pushing the important content high code wise: makes logical sense what a search engines reads at the top code wise is more important than what’s at the bottom, so if you can have the important content higher up, you should.
I personally wouldn’t change the main code to that level just in case. CSS changes are SEO neutral, which is why all Stallion layout changes are CSS and not HTML based.
BTW if you updated to Stallion you might be able to achieve what you want to some degree. Select a left sidebar layout which put all the content on the right and use the content widget area (not available with Talian) for loading widgets directly within the content. Where in Talian there’s an AdSense ad floating to the left/right of the main content, in Stallion there’s also a content widget area there as well that can float left/right or center.
Still wouldn’t be exactly how you want it and would run into problems with the archive pages, but it’s a lot closer to what you want than Talian is. Maybe with some CSS changes you could push the content widget further down the page and put your sidebar widgets within it.
In your first post you mentioned doing this for the larger ad units, upgrading to Stallion and using the 210px wide left sidebar layout would allow for the 728px wide ad unit without any other code changes where the Talian floating ad unit resides. This is a post using the 210px left layout doesn’t have an ad (don’t use ads on that site), but you can see a 728px ad would fit in the main content are easily. You could also with minor code changes have the content widget area load after the AdSense ad unit on the right as well.
There are so many more design options with Stallion as you almost certainly have a Stallion ID would make sense to work with Stallion.