There’s no straightforward way to calculate that with the amount of information that you’ve given.
The coordinates in the horizontal direction are absolute. As I said: 3200 pixels corresponds to one complete revolution, so if you know the circumference of your egg, you can easily calculate how wide the design should be in Inkscape.
In the vertical direction, the exact scaling depends upon a number of factors including the shape of the object and pen motor position. I can give you some starting points, though:
– If you are printing on a sphere, put the pen motor in the top position, and the horizontal scaling is equal to the vertical scaling.
– If you are printing on a chicken egg, put the pen motor in the center position (halfway between top and bottom positions), and reduce the drawing size by about 1/3 in the vertical direction. (Or, stretch it horizontally to about 1.5 X the initial width before calculating the proper horizontal size.)
