Thank you for the answers!
To answer joeblast first;
I do thirty minutes of emptiness meditation after each session of yijinjing massage, and I practice small circulation and bone-marrow breathing 4-5 times a week.
Not sure about the dantien. I can feel it very well, it's like a ball inside my lower abdomen. That's the thing, though, I have no idea how it's meant to "feel". What I got is a warm, tingly feeling. In meditation, when I reach stillness, it becomes less subtle, more electric.
Yeniseri;
I started this training because I wanted a lifelong endeavour. Under the course of the past 4 months I have stopped eating wheat, saturated fats, sugar, and salt. I have also been a vegetarian the past 5 years (with pauses to eat meat 2-3 days a year). I'm gradually moving towards a raw-food diet, which I've understood is the best for cultivation.
You use a lot of unfamiliar terms at once

qihai/mingmen/shenshu are the passes at the back, I think I recall, so do you mean I should spend part of my practice with massage/focus on those areas? Is shougong meditation? I have never heard that term before.
I have not felt any negative effects except the rash and fluctuant emotions, which only appears when my practice is imbalanced, but I know what you mean... I had understood it as such that overflowing from the dantian is a sign that it is close to full, especially when the MCO starts flowing, am I mistaken?
When I follow my practice perfectly the only after-effects are a calm mind, lots of energy, and tranquility that follows me through the day
yeniseri and joeblast, have you done the yijinjing practice described in the book? if so, what were your experiences around day 100, and how did you train?