So what is silk reeling then? What are the focus points in the exercise? I'm guessing they're different for different levels/layers of understanding; if so, what might be some of those differences (particularly for beginners and intermediate levels) be?
Also, what are the sensations one experiences when practicing "authentic" silk reeling?
These are all parts of the same thing:
Someone misunderstanding exactly what is being practiced/conditioned in the breathing (and related) exercises is going to blow the reeling-silk exercises (or misunderstand what is being talked about) and is going to have some wrong idea about "moving from the hara", in addition. I.e., these things are easily misunderstood without a common dialogue established in person. Most of the people I see nowadays who are "using internal strength" are still moving from the shoulders, etc., which means all the talk about 'silk reeling', 'breathing exercises', 'hara', etc., is actually something else and the terminologies are getting crossed. So my recommendation is to stick with absolute kokyu/breathing basics and branch out into techniques and applications only after the basics have been truly ingrained.
As always, "these things are 'easy to learn' but difficult to correct". Then again studying internal strength is very much Aikido because you get to watch your enemies defeat themselves in their rush.