Hubcentric spacer or ring stock wheels

[live&learn]

I have a 2013 Explorer, about 2 years ago I bought wheels for a 2020 Explorer. I’ve been procrastinating on getting hub rings to allow the wheels to be hub centric again and not lug centric. From what I’ve found I believe these are the right size spacers 63.4mm inside diameter to fit my hub and 70.5mm outside diameter to fit inside the wheel. Is this correct?

Also I’ve always heard thin wheel spacers like the ones I posted are asking for trouble because I’m not using as much of the studs threads. Is this a real concern or is this one of things people keep repeating on forums and it’s not that big of a concern as it’s made out to be? So that’s my other question, what’s the better option, the ring or spacer?

 

[Ironworker40]

I never used a spacer but a 1/4'' less thread isn't going to hurt as far as thread engagement. My wheels have the rings. They stay in the wheels, they were in there when I got them and I never removed them in 6 years.
I'm not sure of the diameter.