How can I "Open a new Folder Tab" to a specific folder

As you said - If you assign "New Tab" to ALWAYS open to "My Computer",
this could cause problems with other assignments.

You could implement the strategy I just posted here:

[code]Create a popup Drive List w/ Hotkey only - no button]

or, you could create only 1 dedicated button in the Rclick context menu to open "My Computer" in a New Tab :