Check out the tech sheets for the current Zones (
Vapor Zone), the listed mid-RG is 0.017, not too shabby. That holds true for all the modern Zones except the Impulse Zone, which was a few points lower (had a lower diff, too). Higher than most asyms before the current crop of super-low spin time asyms we have now, spin times in the 8-9s range.
It wasn't until the last season or two that we started seeing <6s spinning balls like the Xception5.0 (the first 5s spinning ball) and the Vanguard balls with mid-diffs in the 0.025 range. Track's asyms from the Freak and Phenom era were in the 0.010 to 0.015 range, spin times over 8s. The Havoc had a very weak asymmetry, I think I heard spin times in the 11s range.
SH