I totally agree with you. Grouping, whether it's subclass of fatty acids or macronutients is usually very misleading. I've reread my post and I admit I've made that mistake there.
I have oversimplified the issue because I feel that this was aimed at a beginner who usually believe that taking flaxseed is equivalent to taking/to benefits of fish oil. There are Omega6 fatty acids that are quite beneficial (I have actually taken GLA but didn't remember) and others who in excess might promote inflammation (LA). I am totally OK with your daily spoon recommendation.
As for heavy metals I would say, depends of "where ya at". Should people who eat "poor" worry about heavy metals in fish oil ? Not in my opinion (I'm leaving the door open for some super toxic chemical that appear from a low reputable chinese producer but the point is this are itsy bitsy things compared to the whole picture). As an interesting note, Kresser (
link) talks about selenium in fish being protective on some effects of mercury.
Can you link me about the 40K VitD ? I've only heard numbers around 10K (~15min, depending on your location and season) and while I think sun fear is exaggerated, 60 minutes of midday sun sounds too much. And yeah you can use D with once per week megadoses but excess magnesium will be peed out so that strategy isn't universal. Blindly loading on the other hand of course isn't optimal.
RDA is a funny thing. I've read that it was invented to prevent soldier from dying of malnutrition. Can't find any sources about RDA pre 1945 but if it's true, check the words. prevention from dying of malnutrition vs. optimal nutrition. Long way in my opinion
Plus bioavailability, mineral blockers, etc.
As for your body, I don't know. I remember when I CRAVED bread, ate it four times a day and was tired all the time. I then FORCED myself to stop eating it. My energy returned and was better than before. I think a lot of food choices are a mixture of desire and (mild) addiction so an obese invidual listening to his body might hear "donuts, donuts all day long". I realize you were talking about supplements and attention which is more rational in my opinion but I still think that the phrase is overused and not of much value and could be more or less replaced with data and daily checks (log/diary of usage, description of physical changes, mood changes, etc). When I feel I want a banana do that really imply that I'm deficient of any nutrient* in it or do I just like the feeling x (maybe French novelist smell nostalgia of grandmas banana tree), which I get when eating it ?
*I've read a study about babies picking their own food and more or less they nailed they RDA all by themselves. Babies being key.