How high can someone place a sample on Transmitter coil? Will the supplements piled in the container be imprinted equally?

Closer is better. We have not determined the absolute maximum distance. We recommend placing the sample directly on the coil, in which case the distance is small. Large vessels like jugs may have some contents further from the coil, but this has not adversely affected performance.

No. The ones closer to the coil will add more information to the scalar field.