A thought while you are putting this together: could you give options for those who just haven't been able to tolerate even tiny doses of methyl B12? I am taking all the other supplements that you have recommended (and have been for some time), but when I tried substituting sublingual methyl (Jarrow) for sublingual hydrox, I got such run-away detox symptoms that I couldn't manage it.
I tried different doses and when I got down to about 100 mcg and that much put me in bed for 2 days, I stopped taking it. I have had to reduce my hydrox intake, also, to very small amounts as it too starting to bring out way more detox than I could handle. I had to lower my 5 MTHF as well. These changes happened after my methylation function improved.
So it would be great to have options for possible responses like this.