here, here. Every time this question comes up I cringe a little.making the point that a lot of practices that are frowned upon are perhaps not as destructive to a decent coffee as some would have us believe
What works for me is:
Firm tamp, light tap, light tamp and polish.
Never get channels, always have clean pucks and group handle.
Seems that someone had a punt at what might happen in the group handle, posted it to the internet somewhere and then forever it became regurgitated law.
Do what works for you I say!