Just a quick clarification:
I think, Shawn, in the quote below,
You're building the energy in your middle Dantain in those two meditations,
if he is referring to the Sun & Moon meditations, means "You are building the energy in the
upper Dantain in those two meditations..."
The upper Dantain is where the "third eye" is.
Hence, his comment there, that the work on the lower and middle Dantiens in Levels I & II is so crucial.
Shawn, please correct me if I am in error on this clarification.
And as far as your original question, coolguy, from my perspective, I agree with Shawn: I have the two meditations in question. I purchased them at the recent Level III retreat, where we learned them under the guidance of Master Lin.
It was emphasized there and I feel it in my practice, that the cultivation of the lower and middle Dantians is
vital to the further advancing work in the upper Dantian.
And I think a 6 month window of good solid work in those areas (and/or about 30-60 hours of
each Level, whichever comes first) is a good rule of thumb.