Just for shizzles and gizzles, I built up a Dura-Ace FW hub and slapped a Dura-Ace track cog on it. Surprisingly, I got the chain line half-decent, but I noticed that there is no room for a lockring. I took it for a test ride and got the cog to spin off fairly readily, so I rotafixed it. What are the odds that this is going to stay put?

Incidentally, I'm running a 42x16 gear [I usually run 42x14 on the SS]. I'm new to FG, but have been riding SS for over a year.