Could you be more specific about how you want us to measure the palm. “The most wide part” is not very specific, because of how the thumb affects the shape of the palm near the base.
If my thumb is pointing out perpendicular to the rest of my fingers, my palm makes a nice arch between my thumb and index finger. At what point does my palm end and my thumb begin? If I close my thumb so that it is parallel to my other fingers, then there are other questions about where to measure from.
Sorry, but I’m supposing that precision is a virtue in such matters.
My suggestion is that we keep the thumb closed, or parallel to the other fingers, and measure across the palm from the bottom joint of the thumb, or “the most wide part of the palm,” i.e. from one end of flesh to the other end of flesh. But it’s your survey. Perhaps this is how everyone has already measured. Once again, I don’t mean to be a pest. It’s just very unclear to me.