Hi Lucy, you may have some competition on the mind/brain chatter front!
What I meant by theoretical spirituality is pretty much what you said - thinking and learned debate as a substitute for practical work - whether on the self, or in the external sense. Especially when it leads to a mistaken sense of accomplishment.
That's not to say that thought and a view on what we should be doing in either respect is not important - it's just that it can as above be such a self justifying trap, and become such a barrier to personal transformation and development.
I guess the sort of overly zealous frontier protestantism you describe is in terms of the spiritual path a sort of naive do-goodery based off an intellectual and fairly simplistic view of 'good'. As such it's (while practical action is hugely important) perhaps at the 'beginner' end of spirituality.
A deeper understanding of the nature of things, and much more important the empathy and knowing/wisdom that arise following life experience and internal self work (especially meditation) seem to lead on in to a much more intuitive, less clumsy and further seeing approach to living through love. A surer and subtler touch so to speak.
Buddhism would say that as a result of meditation and going inwards (the dimension of practical spirituality that delivers real personal transformation - and all else follows automatically from this) we reconnect with our natural knowing and empathy/compassion, and that these with experience increasingly enable us to manifest true wisdom and love/compassion by 'skillful means'.
The interesting bit is that the actions of a highly realised person may appear to somebody operating at the more simplistic and rule based level to be wrong - when instead they are the result of a deeper seeing.
The range of ways we receive insight and open as we go inwards (or just through life experience) is as you say mind bogglingly varied - study, meditation, contemplation and the like seem to be important tools, but heaven knows what the personal path will be. (it can perhaps be described at the general level, but that's not much help on a day to day basis)
This I guess is as you say where a teacher who can read your situation and see past your blind spots comes in, or failing that a self work manual and a lot of self enquiry.
When you reach the point where you can bend the forks I guess that would certainly mean you've dropped any limiting beliefs you had about the nature of the physical reality, and are operating well beyond it. That would suggest progress, but Buddhism would say that it's a catch 22 problem - if you get hung up at all on needing to achieve the objective then by definition you are bound by ego and it's belief systems which will prevent it. Also that the pursuit of 'powers' can as a result of so to speak 'taking the eye off the spiritual ball' lead to problems or block progress - it implies the ego is back in the driving seat.
My own experience has been that meditation and so on produced slow but big changes when seen over the years, although illness and life crises have been important openers too.
It seems too that not only are our paths highly varied, so too are the timescales. Some seem to progress very rapidly, others it's said take many many lifetimes. It seems that the trick is to simply work day by day, that as above to get all hung up and objective driven is likewise to block progress.
Just some personal and borrowed views.....