The more important Swiss airbases are already on the "1940 map", so no further world editing is required.
Thanks to DeanH I have the wonderful hi-res Swiss Fleigertruppe skins for the relevant 109 squads:
Bf-109d CieAv 15 being replaced by
Bf-109e CieAv 15
Bf-109e CpAv 6
Bf-109e FlKp 21
I need to research a bit more to discover the Luftwaffe units involved.
I have FreddyB's mainscreen

I need some hangar screens for those Swiss fighter squads, and probably some other screens in due course.
I'm hoping to find a way of swapping the Swiss files in and out of a standard Dunkirk setup without causing chaos, perhaps by using another exe setup somewaht like the Dunkirk squad mission exes to use alternative file names.
Other aircraft I was considering bringing in to this project were
(1) Swiss MS406 just comming into service in 1940. Like many other theatres this project is crying out for a good MS406 model.
(2) Swiss C35 biplane - Karel has done a few which look remarkably similar including the Czech Avia B34
(3) Swiss D27 biplane - and again Karel has done other aircraft which look remarkably similar
The general setup may be restricted to "squad missions" similar to the Dunkirk squad missions, to simulate the actual dogfights that took place.