I've been doing this almost my entire HBD career (not very long, about 35 seasons or so). A few examples are below.
This guy
This guy
This guy
The C/DH is more available and less expensive than the guy that the game generates at RF. Also, the guy that usually gets generated as a RF, underplays the position and still gives you [-] plays and errors at the position. If you have the luxury of having two third basemen that hit 800+ OPS, then go ahead and put one of them in RF. Or, if you have the luxury of having one of those 850+ OPS game generated RFs that still underplays the position, but is a nice bat, go ahead and play him. However, if you lack the luxury of the two above guys, I think the C/DH that OPS 800 is the next best option. To me, it is better than putting that SS/3b in there that OPS around 680-720. There just are not enough defensive plays in RF to have a guy there isn't a good hitter.