Machines is one thing, lungs is another especially in the water.
The lungs have no sensation.
When you have a snorkel in your mouth you can be flat, horizontal on the surface, or vertical on the surface and still breath through the snorkel without noticing the difference.
The NEDU (Navy Experimental Diving Unit) and all the commercial regulator (and rebreather) testing devices place the pressure probes on the back of the throat for the regulator "test dummy".
Human perception is very important, to the human, but it is very flawed and inconsistent. We are completely unreliable as a measuring device. Even our mood can affect our perceptions, and that is why we try to do blind tests when it comes to equipment that has to have human interactions. And even that is flawed.
The color of an item, like alpine skis affect how people perceive how they perform.
Human perception is extremely important when we have to interact with a machine, but we tend to be very poor judge of a machine performance if it is not instrumented. But, we tend to kid our self. We cannot even tell air temperature, but this another discussion...
To the OP,
Sorry that your thread has a few deviations, but most of the advice you received in the early posts are good.
I do recommend that try to get together with Herman. Whether you end up liking a double hose regulator or not is always hard to tell, but you will gain in knowledge either way.
And most important, have fun diving.
