After several years and too many razors, my favorite razor for a DFS to BBS will no irritation is still the Rockwell 6C. I don't care so much about which metal is used to make the razor. I focus on the shave I get from the razor.
Rockwell is hands down my favorite razor with its' weight and adjustability. This would let you not only get a good razor but also another good plate/top cap for free!!