I bought the non-billet, case-mounted version because it seemed the most reasonable, but will entertain what experienced builders like.
I always thought they were there for rag joints which theoretically would never be on center.Tensioners are trouble used to compensate for junk chain.
420 Is thick and heavy... Is going to robb a lot of power turning it and isn't that much stronger than a quality 410-415 chain... And those tensioner with the spring are more problems... You only need a tensioner with a swing arm with poor geometryAmazon
CDHPOWER I have had on my bike for 2 years of hard work, I often wd-40 the chain guide barrings paired with a 420 chain safer ¡
Chain tention
420 non-oring motercycle chain - Amazon