I see what you are saying grizz, to me the article is contradicting its self. If you read he is combining the 2 to get his total. then it states- So lets just talk about head shims VS Nitro % age and assume the engine is run in. Plug choice is next to each one

15 % .2 Hot
20 % .3 to .4 Med hot
25 % .4 to .5 Med
30 % .5 to .7 Med Cold
but then here is his setup;
My set up on my MG66 FT is this

Shim .1mm and 20% nitro, with med plug LRP #6 , 9.2 mm custom venturi 11.5 mins tank time at average tune , 12.4 mins at race tune. 125 ml; tank. EPA wide open. Turbo Head Button.
so the above makes sense to me,and following that train of thought works for me. so I am running 25% nitro with a .2mm shim pack,plus the .3mm built in gives me the ,5mm that makes my engine smooth and happy. know all that will change when I go back to my byrons 30%. I think I will add a .1mm shim for .3mm shim pack plus the .3 built in for a total of .6mm.
so when I ran the above 30% rule the way it's written I had a total of .8mm total shim stack,[.5mm plus .3mm already there]after run in had to lean the lsn 3.5 turns in causing me all sorts of problems that I never had with my other engines. every time I fired it up I was tuning it. the other engines,7-5ports no problems. set the needles and go. hell once they were tuned I don't think I ever touched them.