Allow tinymce in WYSIWYG to load different skins per content type
I think you're on the right track, but from memory, I don't think you'll have info about the content type or the node form in the $settings and $context variables, As Darvanen suggests.

I'd implement hook_form_alter() to match node forms, then read the content type being used, and store it as a static variable through drupal_static() function. That way you can access the content type info from the snippet you pasted above, using that same drupal_static() function, and then choose which skin to use.