Hello @kiek,
I am one of those who Andre was speaking to.
For me personaly this kind of range would be perfect:
Ground 10nm
Below 10'000ft 20nm
Above 10'000ft 40nm
Thats it. I think if you make it open to define own altitudes with own ranges would be the best way. You will never make everyone happy with suggested of fixed altitudes and ranges.
On the other hand I don't know how "hard" it is to realise it.
Anyways, thanks for you effort and mega software.