I said exactly the same thing GEHELEM yesterday!
60 ° C difference is huge, very good
the fan will be set just above the PCB hole and a lot of holes on the box, my first tests were good, we'll see if it will be like when it's all fitted together.
I put thermal paste between heatsink and case to help a little.
At worst, if that's not enough I would do a tube with the 3D printer to push air into the PCB hole with 1 fan and I would put a second fan to extract.
what I found odd during my testing, if I put the fan 12V (normal voltage) decreased delta : -27 ° C with fan 12V and -32 ° C with fan 9V , even fan, just different voltage means less air flow.
This afternoon I had a new room CCD bigger, with resistance to heat integrated (1.2W) for glass .