Do 217 should be an heavy bomber?

[Dili]

I want to put a Do 217(with Fritz X missile!) in scenario and i don't know if it should be heavy bomber or just medium.
At 16,6 ton max weight it needs a runway of more than a 1km, so for this reason i am tempted to put it as heavy bomber , but i am not sure what advantages it implies also that could be too much.
I remembering reading that heavy bombers don't have a check before bombing, so they will always get trough.
Anything else that might influence?
Or if i fictiously make it with 4 engines is it enough for my proposes of forcing to use a bigger airbase?