Hi Nekomon,
If you were to review some old threads you can get alot good info. Look over the sight and click on those threads that pertain to some of your questions.
As for falling asleep when you do self reiki it is all too common for that to happen. I often go to bed with my hands on my heart and solar plexus and fall alseep before I can get very far into the reiki flow.
Before you begin to work on yourself, set the intention that "if I fall alseep may the reiki energy continue to flow to all the areas of my body that need healing. Let this reiki continue for _____ (you insert an amount of time)." This way you can fall alseep knowing that the reiki will continue and you don't have to worry about it.
The heart/solar plexus chakra hold is very relaxing and lends to peaceful sleep.
Love and light,
Tracey