1. Must be a design that maximises the chance of being found by the search engines.
This has
nothing to do with how you lay out a document. It has to do with content.
2. Must be optimised for minimum execution times. (It will use mysql and php which I'm learning)
The main argument against tabled layout in this respect is that browsers need to render the entire table before they can figure out where to render elements. Non- tabled layouts can execute in linear fashion so it renders faster, though I'll say, in my experience, this is negligible.
In respect to your content, using a non-tabled layout better describes your content, and is an issue that does indeed better supply that content to search engines but also affects accessibility. That is, a <p> means it's a paragraph, an <h1> means it's a heading, this gives context to the search engines. This
<p> I am content</p>
Is much more descriptive of the content than this.
I am content <br><br>
A table is for tabular data, as in a spreadsheet, so it skews the semantics a bit.
In terms of accessibility, when you read a page with a screen reader it's also confusing, it will read the table cells expecting tabular data. Often, tabled layout is accompanied by may other abuses, and the overall effect is that it makes your page less effective.
But in terms of "being found", no real difference, it is not about the layout.
