This is based on the Clas Ohlson case - the largest - code 40-8470
The wavy foam you have to cut. In the lower part the layers are pre-scored and can just be pushed out in blocks. I found I had to glue the wavy layer down when done.
Lower left showing charger slot, leg slots, cut out for gopro mount and two battery slots. Also a small covered section (see next but one pic). Note that I put the batteries in cables down when charged and cables up when used.
Part-loaded it looks like:
Close up showing the covered area:
Case right showing two propeller areas and the radio. Note that the radio should really be the other way round with the antenna towards the front - as it is now it looks natural but when you close the case and lift it the antenna is pointed downwards. This has the effect of pushing it into the foam between it and the propellers and lifting the foam: