Not able to configurate any HTML tag of a table content element with typoscript.
You can add a class to <table> if you set it to the flexform, but only one class. Two classes won't pass the validation.
In css_styld_content points an userFunc to tx_cssstyledcontent_pi1->render_table where the configuration is taken from pi_flexform field.
This is very unflexible, because if I want to change something on a table, I have to write an extension to overwrite the pi_flexform value of that content element. other elements are rendered with typoscript, not with userFunc.