The racing chain we have used over the years has been lots wider. You’ll need the manufacturer’s master link if you’re using one, I would guess not. We had to upgrade our chain breaker as well. Lately using Gold on Gold from RLV and #420 ER gold and black from D.I.D. Racing. We had to do some machining as well to make clearance for the wider chain. Both chains will only stretch a bit more, thats really nice.
Sorry, no current use of Regina chains. Years ago that all we used.
Hope this helps,
Steve