Right then,I've looked up some RLM directives regarding application of winter camouflage.
I hope you won't mind if this is a little bit technical (and serious)
From Luftwaffe Directive Sheet 27 (21/6/43)
"The Ikarin camouflage paint A2515.21 as used last winter for snow camouflage of aircraft should in future be indented for only under the designation Aircraft paint 7126.21".
Now we know what we are looking for.
From Luftwaffe Directive Sheet 43 (4/10/43)
"In accordance with TAGL I Q 2eNo1, serial number 437/43 the following is to be used for the winter camouflage of aircraft and aircraft equipment, provided such latter is fitted to the aircraft or protrudes from it (e.g. onboard armament)
Camouflage paint,white aircraft paint 7126.21."
This order also stipulates using this paint on everything from ground vehicles to tarpaulin covers.
Finally the book Der Flugzeugmaler (aircraft painter) for 1944 states:
"Snow camouflage is applied in the winter months only, with aviation lacquer 7126.21. Paintbrushes are best used to apply the colour"
Instructions also state that aircraft maintained or overhauled at maintenance units were to be returned to Eastern Front units with a solid white coating. I bet any money these were sprayed, whatever the book says. I've got photos of it being done.
I would add a word of caution. Contrary to the popular German stereotype, Luftwaffe units, particularly those a long way from Berlin, seem to have been very remiss at following the constant stream of orders and directives emanating from the RLM and Luftwaffe. Both organisations continually complain about units "doing there own thing".
(One inspectors report accuses groups in France of ruining their aircrafts finish by polishing them.)
That doesn't seem to have stopped them issuing reams of orders and corrections that any red tape bureaucracy would be proud of.
Serious hat off now and back to modelling!
Cheers
Steve