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.

Can one do remote distance healing with the Spooky 2 Scalar device?
You can have a try. Here are some sharings from some scalar users: https://www.spooky2scalar.com/qa/can-i-just-put-a-photo-of-myself-in-the-scalar-field-or-on-the-transmitter-coil/
Hi, Alice Ihde. Here is a link for you and that may help you: https://www.spooky2scalar.com/qa/can-i-just-put-a-photo-of-myself-in-the-scalar-field-or-on-the-transmitter-coil/
Normally, there are convection currents in water. So, over time most of the contents would be near the coil for a few seconds before moving off. My gut feeling is that the influence range from the coil does extend out, like an aura.
Isn’t this information? Therefore, distance should not be an issue no?
I treat it as a homeopathic imprint that you tap (percuss) against your hand for 30 secs (I believe it is or ok to do longer) to mix it up. So this way I hope it’s getting mixed equally.