Interesting about the plastic / nylon hb rings . I ran RH Cups on an old VW years ago with rings and had no problems .
I see you can get alloy hb rings now as well . Any good ?
I ask because i'm wanting later on to go to a 18x8 rim , off set is 38 but can use spacers but the only cb i can find at the moment is a 73.1 so hence rings will be needed to get to a cb of 65.1.
https://www.ebay.com.au/itm/142476668057?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649