Here's a link that describes offset and back spacing:
https://www.rsracing.com/tech-wheel.html
Basically, the more back spacing a wheel has, more of the wheel is going to be on the inside of the wheel well. Less back spacing, it will stick out more. That's a rough description, but it's the basic concept. If you know the width and backspacing of the wheel, that will enable yo to calculate the offset.
To the best of my knowledge, a hubcentric wheel puts more of the load of the wheel on the hub, as opposed to a lugcentric wheel.