I have a PC with a standard English keyboard, not a Mac, but I will describe what I currently do that could maybe be adjusted for Mac:
The handy thing about high-volume coarse labeling of Unknowns is that a set of typical ids can be accessed with 1 or 2 keys with the left hand on the keyboard while the right is on the mouse to do the add ID clicking : a gets you Angiosperms near top of suggestions, plus easy to get Araneae, Arthropoda, Agaricomycetes with a couple more letters; s gives Tracheophyta (no idea why but ok); d gives Dicot.; f Fungi.
The efficiency issue is that either the -> arrow key or Shift-+ to get you to the next record needs you to take your right hand off the mouse to tap the keyboard. So, I used the utility SharpKeys to map right arrow behavior onto the F2 key, which I’ve never used otherwise and is right there on the left for my “keyboard hand”.
If anyone else has efficiency tips for their own setup, I’d be interested to hear about them!