"Trying to get an option in to change/choose the menu type would be quite a lot of work.
If you always want the articles to be saved as 'Open Source MSC', you could simply change the 'component' template file for articles that comes with Add to Menu:
/administrator/modules/mod_addtomenu/addtomenu/components/com_content/content.php
Especially look at the part:
", "'urlparams' => array(
", "", "'option' => 'com_content',
", "", "'view' => 'article',
", "", "'id' => '$cid',
", "),
Change the option to whatever MSC uses. And change/add anything else that needs to be in the url."