Flush Stock Wheel Spacing?

I can't seem to find a whole lot of info regarding wheel spacers on here. Seems most people just get new rims with the backspacing they want, which is fine and all, but I actually really like the stock multi-spoke style wheels, and don't feel like investing a couple grand into a new set when I like these ones. Does anyone know the spacer size to get the stock wheels flush or just ever so slightly tucked? I've seen 20mm pics and they look to poke just a wee bit, so should I do something like a 15mm, or will that still poke? Any recommendations on where to get wheels spacers and other aftermarket accessories for these cars? Looking at the hub and bolt pattern, all the Hyundai Gen Coupe, Genesis Sedans, and Genesis brand cars seem to share the same configuration, so will any spacer that fits one, fit the other, or will I need to start shaving wheel studs and stuff if I get spacers not specifically designed for the G70? I've been away from the KDM scene for a bit, so trying to get reacquainted with the various platforms, and the G70 in particular. Any help is much appreciated, even if it just links to somewhere I can find the info! I've searched but to no avail, and I don't want to buy the wrong thing since getting things to NL, Canada is a pricey endeavour; returning stuff from here is doubly so...

Cheers!