I'm more in the Branford school of practicing what you'll actually play on a gig.Hours and hours of overtones. Look at Liebmans book developing a personal sound K
I did overtones a little when I was a teenager figuring out altissimo (early 1980's), but hardly any since, unless you count the altissimo notes themselves. Kind of like riding a bike or learning to drive a stick, IMO. Once you get the knack, no need to drill anymore. Then practice to learn new stuff. Maintaining what you've already learned should mostly happen coincidentally.
Plus, spending an inordinate amount of time working on one tiny aspect of your playing makes no sense. There are only so many hours in the day. Spend your time on the hard stuff and the important stuff.
Also not a fan of Liebman's tone or style at all. He's a brilliant guy. But I don't want to hear him play or sound like him.
Regarding being original, that's easier said than done. The masters copied their idols as well, so nothing wrong with that. Standing on the shoulders of giants is a very valid approach to just about every endeavor in life.