What are the dimensions and padding details of the stool's seat?

The stool's seat has a diameter of 14 inches with 0.5 inches of vinyl padding riveted through the steel seat pan.

What is the weight capacity of the NPS 6430 6400 Series stool?

The NPS 6430 6400 Series stool supports a weight capacity of 500 lb.

double click image to zoom in

NPS 6430 6400 Series Fixed Height Heavy Duty Vinyl Padded Steel Stool - Backless - Supports 500 lb, 30" Seat Height - Gray Seat/Base

Sturdy 0.88" O.D. 18-gauge steel tubing with fixed legs.
Seat has a 14" diameter with a 11.5" diameter, 0.5" vinyl padding riveted through the steel seat pan.
Foot rings have a 0.63" O.D. and are welded to each leg by four contact points for added rigidity.
4.75 mm MDF board with rivet heads fully embedded.