Tonights moon taken with 400mm f5.6 and TC201 2x converter. This converter is designed for lenses up to 200mm, and not recommended for the 400 lens so not a bad result. ISO400, lens wide open so effective aperture f11, shutter speed 1/200 to minimise any vibration effects.
Modifications to kit before trying this combination were making a new mounting foot extension for the lens ( see post in lenses forum ), adding a 1.5 kg counterbalance to the Manfrotto 501 head and suspending a 5kg weight off the tripod main boss to keep vibrations to a minimum.
Cloud cover has now come in or I would try a mini comp with Sassan and add my last TC. Not that that could really compete as it would only give 1600mm f22 wide open.
Don