Well I do not think I have a big secret, but this is what I do.
I fill it up to the legs, and put the core inside.
I cook it for almost 20 minutes more than regular pan.
Only what is different is maybe that I make a choclate core the day before, to replace the steel one.
You only add little oil into the core and let all sides be oily. Then lett it stand uppside down to get out the over oil. Melt some choclate and pure it in. Full.
Let it stand cold night over and releece it from the core. It is ready to use.
When I finich the cake I do not open at once. Let it cool for 15 min. After you cool half side at the time.
It sounds maybe simple, but I have had disasters too.
As it has become a favorit cake for many of my customers, it has not allways been my favorit. It needs more care to make than the others.