[hsusmann]

As for your reversing the ant wires, could it be you had
a primary wire swapped with a secondary wire?

That would clearly cause a problem.

Simply reversing the polarity of either the primary or secondary
should not have any effect, unless there are other parts involved
that I am not aware of.

If you don't have a very long antenna (you had said 4 ft ??) then
I can believe that touching the 6A7 grid cap would still increase
the volume as your antenna is too short to be very effective
at Broadcast band frequencies.

Keep in mind that one wavelength at 1000 kHz is 300 meters so
you need to have some length to that antenna wire!

Herb S.