Right then,time for some contemporary evidence,all B+W and all from my hard drive.
Firstly all the images I have found of this type with a black lower surface feature the reversed pattern of an RLM75 base colour with lines of RLM76 oversprayed,that much the restoration has correct. I have no idea if this was always the case.
For you expert sprayers,I doubt that this would pass muster.
The aircraft without a black lower surface are in the more common scheme of overall RLM76 with mottling or streaking in RLM75. This matches the Heinkel factory scheme approved by the RLM.This scheme was common to many nightfighters and features in most profiles of the He219.
Here's an example. Notice how diffuse the oversprayed colour is.
Finally a model for the 76 over 75 over black scheme by Osvaldo Viggiani,nice job,but he is wrong to say "It is irrefutable that almost the all late period Luftwaffe night fighters such as the He 219, Ju 88, Bf 110 and Me 262 B1 u1 were painted using a reverse pattern camouflage of 76 Light Blue over solid 75Grey Violet, on squiggle, net, irregular blotches and cross hatched style."
As far as I can establish (nightfighters are not my main interest) the black bottoms were fairly short lived and given the orders for amounts of different colours to be applied,by weight,an overall base of RLM76 was required. Logically overspraying a lot of RLM76 (see the pictures) over a base of RLM75 is a waste of paint,something the Germans were hardly in a position to do.
I hope this has spread more light than heat,back to Trey's excellent model now
Cheers
Steve