Tightening a cog without a chain whip

Yes, that is what I am saying. Something about using a lever to turn a screw is better than hitting something to turn a screw.

No one seems that bothered, including me!, but try hitting a lockring on with a hammer and then see if you can still screw it on more with a lockring tool.

And I have found my lockrings do need to be that tight to avoid the cog unscrewing when skid stopping. Or they do on the cheap hub that I am currently using, guessing the cheap part is the reason for the tight lockring...

I think you'll find I haven't argued that using a lockring spanner isn't more effective than a hammer/screwdriver, I said that a hammer/spanner will do the job. Which it will. If it didn't for you, then you obviously didn't tighten it enough, that doesn't mean it's not possible. Whether you can or cannot get it tighter with a lockring spanner is irrelevant, as it doesn't need to be tighter.