20" ones are the only ones with wide enough wheels for the Z, and with that go 20x10 +25 in the back, and 20x8.5 +30 up front. Those are the closest to decent offsets that you will find in that wheel. I'd still suggest a 10mm spacer up front, and a 5 or 10 in back to have the wheels flush though.
Personally, I would spend a little more money and get get a higher quality wheel for the Z. Konig's aren't bad, but there are certainly better ones out there...but if that's what you want then what I mentioned above will work
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____________________ PROJECT DiaD - Sold but not forgotten!
The first testicular guard, the "Cup," was used in Hockey in 1874 and the first helmet was used in 1974. That means it only took 100 years for men to realize that in order to work the penis, the brain must remain whole.