Since no one else has, I'm providing a link to the most legible version of the above mentioned document I've found on the web.
http://www.billymegawatt.com/uploads/6/8/4/6/6846461/norton_750cc_service_notes.pdf
35 years ago, I owned both a Mk II 850 and a 72 Combat. My first Mk III I kept the engine stock, other than peashooter silencers, re-jetted carbs & balancing the engine. What say the gray beards, regarding installing a 2S cam in a Mk III engine? I ask, as I suspect when I Rockwell hardness test the cam on my 2nd Mk III, I may be in the market for a new camshaft. Andover Norton prices the standard cam & the 2S the same.
I had downloaded a copy of that set of notes. I think John Hudson's wisdom was carried over, but of course there is editing involved.
What I have is just John Hudson originated material with no editor I am aware of. I have seen somewhere online a copy of Johns notes exactly as I recall them in '75. I did download them, but they were lost in a typical home computer catastrophe! My wife typed them up on a small portable typewriter from a simple 1970s Roneo type spirit copier, there were no graphics at all, just text, and no photocopiers at work let alone home in those days!
Perhaps what I should do is cross-check the words attributed to Mr Hudson, at first glance, the main issue is ordering of comments, obviously the editor has applied what he sees as a logical order, why not when aligning material from various sources.
Regarding your cam, the choice is of course yours. Many will tell you what an excellent cam the standard item is (including John Hudson). Having both raced and toured a 750 with small ports and a standard cam I can only agree with those comments. If your MkIII cam has lasted this long there is hope for it continuing.
I would go back to what I said earlier, clearly state your requirements and be brutally honest with yourself! Why would a 2S cam improve your riding experience 35 years on? It clearly works for some as they tell us about it.
When selecting cams for circuit race bikes it comes down to variations on two themes, PW3 or 2S! Bearing in mind that 4S is a variant of 2S, as are several of the cams mentioned here over the years I have been a member.
In my current race motor I have run an actual PW3 and two variants on the 2S theme. I enjoyed the PW3 most and want to go back that way, but I have no doubt the 2S and variants work well!
For a road bike I am pretty sure I would install a standard cam!