The seat height is only defined by the gas lift and is the same for the Petite Gokhale Pain-Free Chair and the Standard Gokhale Pain-Free Chair.
The Petite chair has a smaller seat pan and a smaller and lower back rest.
Q: I have a higher desk. I am 5’3”.
A: Standard Chair with a Tall Gas Lift and foot ring. Make sure to measure the desk surface and that your arms are comfortably at rest on your desk or table. Compare the measurements of gas lifts listed on our shop page.
https://shop.gokhalemethod.com/products/gokhale-pain-free-chair