Thank you womcat66, your kind words are much appreciated =)
So, *cracks knuckles* onto the answers. Firstly, as far as eyes-open versus eyes-closed, I don't know which is better; that's something I'm currently looking into. I've yet to try a dose with my eyes open the whole time, but any time I get a reaction from a dose while my eyes are closed, opening them seems to make the effects dissipate. Of course, though, others on this forum has supposedly gotten open-eye visuals during a dose by just staring. Like you said, though, staring may be the cause of certain visual effects in itself.
As far as controlling your body is concerned, I've had more luck, personally, when I let my breathing and heart rate increase. I have no reasoning behind it other than possibly a placebo for the real effects, or perhaps it's simply allowing my body to produce the chemical reactions to the dose at a faster rate. Of course though, I don't hyperventilate; if it's distracting you from the dose too much then it probably won't do any good at all.
Your main concern is interesting; as far as being immune is concerned, it is impossible unless something is interfering. If you are deaf in one ear, then the doses simply cannot work on you. And I don't believe I-Doser kills braincells, it merely puts us into a biological state similar to when taking certain drugs - but without said drugs actually in our body. Our body may produce dopamine or serotonin when taking a drug, and that can be reproduced. But other biological effects dependent on physically taking the drug like "cotton mouth" from smoking marijuana are impossible to achieve through I-Doser (and anyone saying they got cotton mouth most likely had their mouth open at some point and it dried out during the dose, similar to waking up with a scratchy throat).
As for increasing your odds of having a successful experience with a dose, try to think of all of the external variables, and change them one by one. The volume of the dose, your positioning, the lighting; what works for one may not work for all. Also, because brainwave patterns change during sleep, have you tried taking doses when you're so relaxed that you're almost falling asleep? If it feels like you're only staying awake because you're "hanging on" to the dose, then there is a good chance you can enter a self-hypnotic state and the dose effects would be amplified. Just make sure not to fall asleep!
Hope this helps!