You have more patience than I.
I had a sending unit stuck. Heated, cooled, soaked, lubed, nada. Then I drilled a hole through a six point socket, put the socket over the SU, using the holes in the socket, drilled through the su, hammered a steel pin into the socket/sending unit, bolted the manifold to a piece of 8X12 Fir, put a breaker bar on the socket and using a long snipe started too apply a lot of force. Broke the manifold, bought a new manifold.
Nothing to it, piece of cake!