I'm currently riding a biopace 42T chainring and a 16T DA sprocket. I like the ratio as a nice "spin" gear but would also like a low-cadence "big" gear. I do have a fixed/fixed hub, so I'm good to go in that regards.
I just threw my chain and have decided to ditch the biopace, so the only thing I'm keeping is the 16T cog. I can go with either a 47T chainring and 16/18 rear sprockets or 42T chainring and 14/16 sprockets.
Is there any advantage of going one way over the other? The only thing I can figure out is that the 42T chainring option will allow me to get a second DA cog.