Do you know a way to attach the places I have highlighted?View attachment 800840
These were hinges with a kind of clamps/buckles attached to the inner rings going around the engine. These clamps could be dismounted to remove the cowling panels fully or after removing the hinge axis one of the sections only. A quite similar system to these used for the Fw 190 and La-5/La-7, IMHO.
the pic source: Triebwerksintegration – Focke-Wulf Fw 200 "Condor"
the source: the net.