No argument on "right way or best way," just some ways are more reliable gauges of effort....if there is such a thing when basing training on HR. I'll stand by my assertion that the %LTHR is superior. If %LTHR wasn't so effective, serious and professional athletes wouldn't use it, and their trainers and coaches wouldn't prefer it.
But, as I also stated, HR is a decent (albeit imperfect) secondary reference point. An actual gauge of work being performed, in real time with no lags, is power output. But, that is not what this thread is about.