Yes, I absolutely agree. Thank you for your very helpful comment!!
2 of the mentioned books I have already, the three visions I am reading right now, there are also lots of infos about the hell realms ;-)
In Pa Auk we/the nuns said: falling into Bhavanga. The antidote was meant to be concentration, which I found a little difficult to put into practice. At the time I told myself that it is probably just patience which one needs, until concentration gets better through continues practice. I also remember that somebody else said not to focus on it. In the training there, one wouldn't do that on purpose anyway, because it would just appear as a destruction, which should be avoided. Still it just happened to people... Anyway all of what I write is to be treated with care, because I can only repeat what I understood.
I am not so sure that the meditation on breathing is the right thing to practice at any point. I seriously think that it can be very important at certain stages to let go of it, as you said yourself, it is quite easy to get attached to pleasant mental stages, which in themselves are not bringing wisdom. I agree that getting the right meditation instructions from an experienced master is extremely helpful, or better said: absolutely necessary!