gyozadude

Sounds like an excellent fix and should be very safe if the cassette lockring is snug and there's no play. As to the width issue, I ride wide 1/8th inch chain on 3/32 width S/S freewheels and no issues and longevity seems okay, but I'm not putting 400km/wk on a small cog.

However, I'm surprised by the chain chatter. Are you sure it's the chain? The fit might be fine but if the spacing is a tiny bit off, you may need to check and adjust the outer H-limit set screw if you haven't adjusted it already. Typically, the chain width should be fairly tolerant of the cog width, especially if the difference is very small. If you are worried about the chain compatibility, different makers will vary in inner/outer widths for a particular chain for a particular number of rear cogs. Among 8spd chains you probably have 6.7mm to 7.0mm outer width. And 9 spd chains go from 6.4mm - 6.9mm. You might be able to find some middle ground on a chain. I couldn't tell you which brand or model right off hand. But at one time, I used to have a table somewhere written down on brands, models and their widths.