When it comes to scopes on DR the only one I find that doesn't screw up the looks (and balance) are the small 1.5-5x20 VXIIIs and similar size.
The Varipoint 1,1-4,4x24 30mm from Zeiss are wonderful scopes, but just look wrong on a slender doublerifle, too big and bulky...

I had a Mathelon doublerifledrilling made for me in 2008, and it had a small leupold in a pivot mount. I tried a 3-9x42 Zeiss on it, but that just looked silly.. The small Leupold definitely makes it a nicer looking gun.
I'm now using a Docter sight III on it which I find great! 100-120m shots are no worry, and it is very quick. Scary combination..

I'm planning to get one of Peters C-class DRs in .450/.400 one day soon. It will wear a 1,5-5x20 as well.