Please don't feel you have to reply, but FYI it was Brett Scelley a decade ago who told me that he needed at least an 8-9kg spread to effectively handicap within the rating bands. That was at a meeting in Petone because NZTR had asked me to analyse the impact of the handicapping changes that had occurred following the Mark Webbey review a couple of years earlier, which we did pro bono.
What we found then pretty much concurred with his thinking. This from the summary of that report.
"The analysis clearly shows both that higher weighted horses are significantly outperforming lower weighted ones, and that females are significantly out performing males."
My current data says that the situation has worsened if anything. Not a great way to create competitive racing that will build wagering revenue.