Oz Vega wheels

I did a search, sorry if this has been discussed already. I have two sets of Oz Vega wheels and one pair. I noticed differences in all of them and am curious to know more of this models history. My first set the face gets sandwiched between the rims, the pair I bought second these are 16" but the faces are the same size as the 15's. Also both rims go on the front of these which made me think they were two piece(I have not split them) until I got my newest set. These ones match the 16" centers taking both rims from the front but they also have added markings. 
first set.

the pair I bought.

the new set. 

So you're saying some of yours are Rim/Center/Rim while the others are Rim/Rim/Center?

I've got a set of OZ Vega three piece 16s that(IIRC) are Rim/Rim/Center. Want another set for parts?

Some are rim/center/rim others are center/rim/rim. I've read bbs rims fit, ive also read they fit but are not centered by the face only allowing the bolts to locate it, anyone know either is true? I'm building the new set for my opel and am wondering how you measure for barrel width? Curious if there is a reason for the difference in the same model as it does not seem to me to be a year change thing, and do they take the same rims?