Glad you got it working!
I am sure the MFJ could be made to work, but I do know that LDG products are "First Rate" and probably have more filtering.
The MFJ tuner was doing this weird stuff when I used it just with the KX3. I believe the MFJ tuner was bad. A replacement may have worked great and provided more flexibility as I plan on feeding a secondary antenna with ladder line. I decided that I wanted something I didn't have to wonder about.
That being said I had a chance to use an MFJ antenna tuner, those things are awesome, though a little big to take ultra portable.
Thanks for all the help. The 1:1 balun has reduced RF getting back into my shack. I pushed the power to the max I can drive (12w in ~450 ssb out) and there was no longer a hum in my headphones