I don't know the teaching of Bill Gleason.
As far as I know there are a whole lot of different ways to use reverse breathing. (,,,)
To my experience the most difficult part of reverse breathing before it comes to images or intent is first to really manage the physical part of contracting and expanding the abdomen. (Not the chest.) Because as far as I understand it, this is about actively and correctly moving the diaphragm, the pelvic diaphragm and the inner mucles of front and the back. Which is not easy to do.
Although I´m quite new to Aikido, I´ve been an "obcessed" freediver for over 20 years now, and breathing (as you can imagine) plays a big role in there.
Carsten Möllering has hitted the spot on his comment. Breathing is only diaphragm! Big expanding chests burn down more energy (oxygen) than what they can intake.
And Men (males) are worst "breathers" than females and far worse than children... Have you noticed how a baby breathes? only diaphragm work.
As we grow old we accumulate some "vices" on our body movements and breathing is no exception (and again, male "machos" with big inflating chests... get on the loosing side of the breathing coin)
Relaxation is the mother of breathing...
In Aikido I don´t have the slightest clue on how to direct the energy, but in freediving (if relaxed) you can redirect energy from less used muscles/functions to where it is really needed.