Narrow gauge trucks came in many wheelbases, far more than most standard gauge trucks of the last century.
A 29 inch N scale wheel would be 40 inches (39.875) in Z scale. It might be hard to find such as freight wheelsets.
Z scale 36 inch wheels are very close to N scale 26 inch, common on D&RGW cars, and many other roads.
Z scale 33 inch wheels are exact for N scale 24 inch, another common size, especially on the EBT.