after 3 days of trying all suggestion given here and elsewhere, heat, 3 kinds of pentrating oils and catalysts and a lot of brut force the Jet Holder was finally extracted. And subsequently replaced.
The long story:
After nearly rounding the hex head with a socket wrench, I moved up to a hand impact wrench. And completely rounded it.

At that point there was not much to loose so I grabbed the next smallest socket and hammered it onto the soft brass, making a SOLID fit. Then using the rachet with a pry bar I managed to get about a 1 millimeter turn on it. So reversed my force and tightened it back 1 millimeter. and back and forth I went until after about 10 minutes I got a full turn and it broke loose and I was able to unscrew it all the way out.
Tomorrow I'll wire brush the threads which are a little crusty and finish rebuilding the carb. I'm hoping rebuilding the carbs solved the power loss issue I asked about my previous thread.
Just can't say thanks enough for all the help from everyone. I'll definitely be hitting the donate button shortly.