Isn't the highest height possible in the game exactly 3000m (corresponding to 255/255/255 on the height map)? This would render mountains higher than the lower alpes impossible to create.
The highest point on a map can be 4024 meters or something similar but surely 4000 and a bit.
A Mt.Everest could only be possible if someone had the patience to set a new 0 Meters Value e.g. if the Valley beside Everest had 5000 Meters set this to 0. So that The highest possible point would be Mt Everests altitude. Surely would the altimeters show at the highest point 4000m and so on. The altitude performance would be false and the clouds would be 6-7000 meters high....
And it would be big big work to transfer the highdata. If it just would be to darken map_h..., the map_h dark values are higher definition mesh model than the bright, e.g. the high difference at the low values is e.g. 10 meters per value +1 while at high altitude it is e.g. 30 Meters per va
I tried it once and got a map made. But not only were the mountains after a certain height all flat, moreover many parts of the high mountainous areas were the oddest type of terrain and color imaginable. It was - and this is a very approximate description - as if you were looking through the terrain at a deep blue expanse of water ... very weird and not at all usable in any way at all.
So in short, trying to make a map of that height would be a waste of time for Il-2 ...