Measuring a saddle

[dwi]

I'm advertising a saddle to sell, how do you measure the seat size? With the tape measure tight across from pommel to cantle or laid flat along the surface of the saddle pommel to cantle?

 

[CBAnglo]

From the middle of the nail in pommel to the middle of the cantle.

 

[moodiestmare]

You measure it from the nail on the side at the front to the middle of the back