We call them 8`s over here in the UK and near enough 50% of shooters use these at all ranges and beyond 46 yards never mind 16. They break everything at any angle at least as well as 7.5`s, (which are US 8`s). In fact we only drop down to 7.5`s for so called hard to break targets such as rabbits. I have managed to convince myself that even then there is no tangible difference unless the rabbit is edge on and lets be honest that target is hard to break period.
The only time I have noticed a visual difference in breaks is when shooting very large (by our standards) shot such as 2.4mm 7`s. Close targets smoke just fine but less so at distance compared to much smaller shot. This is why almost nobody shoots shells bigger than US 8`s, including George, Richard, etc.