Hood, if you put Mac and Mats as co-No. 1s in 1983 and BB and JC as the same in 1976 -- I have no issues. I would go with Mats and Borg alone for those years -- but, it's debatable, and to leave some room for error is a very sound idea IMO.
I mean the list you presented here is, if we exclude these very few debatable years, perfect. The finest I've seen.
Sgt John has made some stunningly great lists also -- but this one by you Hoodjem is just sublime. Especially since you leave room for error and do not restrict yourself to one name per year if there's a legit debate to be had about those years.
The next step would be a thread about the strongest No. 2s throughout history. Not everything is about being the top dog...