We have tried following the original recipe from Pacaud. Beating the eggs for 30min is clearly wrong, about 4 to 5min gives good results (or until the eggs quadruple in volume).
The temperature of the chocolate sabayon is crucial for it to set at the correct consistency, closer to 70C it will resemble a crème anglaise, 75C a soft flan.
After a couple of iterations we got very good results:
We really couldn't find any decently written recipes, so we added ours to our blog.