I help a novice triathlete with her bike. She had an '88 Centurion Ironman, Nitto B115 bars, and bought a cheap set of Ascent aero bars, which worked just fine. She moved up from C&V to a 2006 Team Fuji carbon with a Fuji bar, clamp size 31.8, but the bar itself is a lot smaller in diameter than the Nitto.
On the Nitto, the toothed shims worked just fine. On the Fuji bar, they are still way too big.
The gap between the bar and the clamp just too big for the shims to fill.
Do they sell different size shims alone, or does she need to find a new set of aeros? I'm a C&V guy, so the modern stuff is unk to me.