One way that I like to do this sort of thing, but which does require access to code, is to create a new dropdown attribute such as
size_fit (tip: don’t forget to add it to your attribute set).
Next you add the options to the attribute. The trick here is to give it a label such as “Button Down” in the Admin View, then the ID of your static block in the appropriate Store View(s).
Now that your new attribute has been set up, you will choose the appropriate Size/Fit option in your product administration that corresponds to the static block you want to display for that product.
All that is left is a little layout coding and your products that have their Size/Fit attribute configured will show a new tab on their product display pages:
Create a new template file at:
<?php $block_id = $this->getProduct()->getAttributeText('size_fit'); ?>
<?php if ($block_id): ?>
<?php echo $this->getLayout()->createBlock('cms/block')->setBlockId($block_id)->toHtml(); ?>
<?php endif; ?>
That will load and display the static block that corresponds to your product’s attribute value (if any).
Lastly, you just need to add this new block to your product display page by adding the following to your catalog.xml or local.xml layout file.
<action method="addTab" translate="title" module="catalog">
Using an extension such as Mass Product Actions in the linked blog article makes it very easy to configure your products with the new attribute value.