Ok I added per widget config options. You can override any of the tinymce config elements using the same syntax.
Setting {options {editor xinha}} will override the default editor for tinymce or xinha, this already worked as it was built into the richtext widget origianlly when we still supported RTE.
I'll see if I have time to get the OacsFS plugin to work on TinyMCE.
It probably will take 2-3 hours. One good thing of these editors is the plugin architecture. Both editors are very easy to add new plugins.