I need to have B12 levels around 1000 to feel OK. But the level itself isn't that important, If I drop from 1000 to 900 I feel just as rubbish as if I drop from 200 to 100.. In any case I like to hold it steady at 1000 because that's what works.
Vit D, you should try hold that at 120-150 but certainly over 100.
I used to have knees so sore I couldn...