Wheels & Tires - Preferred way to add spacers?

I am a bit confused with all this terminology. What is the difference between hub centric and wheel centric and which is preferred? I am not talking about adapters but the single spacer itself.

Right now I have upgraded to longer ARP studs and running a cheapo 3/16" Doorman spacer for clearance issues. I want to run a thicker spacer for aesthetics but concerned about safety.

A hub centric spacer which is preffered has a pilot that comes out to make the wheel hub centric which helps to prevent vibrations. I recommend getting a good quality spacer like the H & R brand.

See this thread: http://ls1tech.com/forums/wheels-tires/1536044-new-wheels-spacers-added.html

If you look at the smaller round opening and see the pilot extruding out. That should be hub centric.