EW, another option is a cape gun. I have one that is regulated perfectly for both the shotgun and rifle bores so it might as well be a DR.
I have a drilling as well and although I'm glad that I have it, I can only say that as a shotgun it is pretty good and as a rifle it is pretty good but neither is great. Fairly comfortable 7# to carry in 7x57R.
It could be better with a set of claw mounts but they aren't there and probably aren't worth putting on.
A relatively cheap cape gun that I have patterns Brenekes into 1.5 at 50yds right under the sight and the rifle shoots to the bead at 100.
I just picked up a hammer cape and that has an integral tang sight which is a nice touch.
I would probably take either out before I took the drilling.
Had a BRNO combo with QD mounts that regulated perfectly ( I regulated it)
Shot a boar on the run once and put the two rounds through the same hole from coming and going angles. Gun was too clunky and off it went.
The drilling paterns shot where you want it but forget about slugs.
Others might do better but I don't know.
The Kreigoff DR drilling is great mechanically, but IMO it looks like a pig.
24" barrels which are way too short for a shotgun ( no swing) and that third tube is a 20 ga.
Although the 9.3x74R is nice, what are you supposed to do with the 20?
My feeling is that if you want a drilling it is because you want one. Love my drilling, makes things seem that much more nostalgic, but I have to be on my toes with the Greener safety. If there was one that was actually regulated for slugs that would be excellent. I refuse to take the reamer to mine.
I understand the desire for a DG rifle, but you don't want to buy a beautiful rifle that might be too limited in scope, especially in the case of a drilling, DR or otherwise.
BTW - the only limitation with 16ga is that it won't carry buckshot larger than 1 unless you load it. That's if you have the need for buck.
Enough rambling.
Good luck with your purchase.
Tom