Cecil Moore wrote:
The other 10% is the traveling wave that gets radiated
of course (neglecting losses).

Absurd. Current does not "get radiated".

Please explain how one would go about getting "standing wave current"
to flow through something - anything - like a measuring instrument for
example.

Opps, standing wave current doesn't flow so you must
have meant how does one eliminate reflections so that
nothing except traveling wave current is present.
Do you need that explained to you?

You claim that W7EL measured the phase shift of standing wave current.
He of course made no such claim. So yes, I need you to explain how it
is possible for someone do measure a "current" that does not flow. This
should be good.

ac6xg