HotTabs provides commands and matching shortcuts that will let you press:
Cltr+Alt+Num1 to go to the 1st unpinned document tab,
Ctrl+Alt+Num2 to go to the 2nd unpinned document tab
Ctrl+Alt+Num3 to go to the 3rd unpinned document tab
etc...
Ctrl+Alt+Num0 to go to the 10th unpinned document tab
and
Cltr+Num1 to go to the 1st pinned document tab,
Ctrl+Num2 to go to the 2nd pinned document tab
Ctrl+Num3 to go to the 3rd pinned document tab
etc...
Ctrl+Num0 to go to the 10th pinned document tab
It selects tabs in the document well.
Like these:
Note that there is one pinned tab on the left and three unpinned tabs following it.
Ctrl+Num1 will go to the first pinned tab. Ctrl+Alt+Num1 will go to the first unpinned tab.
With the commands exposed in Tools->Options->Keyboard, you can apply your own keyboard shortcuts to these commands.