What exactly is a "clock difference?" I don't know where you came up with that concept, but I definitely do not agree with the math you are applying. I agree that a longer flight is usually more tiring that a shorter flight. But simply adding flight hours to time change to come up with some kind of metric is definitely fuzzy math (to put it gently). When I used to fly from NY to Buenos Aires for business a few years ago, that flight was about 12 hours long, with 1 hour time difference. Using your metric, that would be a "clock difference" of 13 hours. While the journey was certainly tiring, I can tell you that the jet lag I would experience after that flight was nothing like the jet lag after a return flight from London, which your metric gives a "clock difference" of only 11 hours. I can tell you that I most certainly was not waking up at 4am after the flight from Buenos Aires...It's not the same issues at all. Flying West is no issue, in either case. Flying East is the issue, and there's a huge difference.
Flying to Europe takes 6 hours on the plane, plus 5 hours of clock change, for a total clock difference of 11 hours from takeoff to landing. You can leave Newark in the morning and be in bed in your London hotel at a decent local time, ready to start a work day the next day at normal business hours. Coming back to the East Coast from Hawaii means 12 hours on the plane, plus 5 hours of clock change, for a total clock difference of 17 hours from takeoff to landing. That's a HUGE difference. It's almost an entire day. To mitigate some of that difference, I'm recommending doing things as early as possible local time while you're in Hawaii
And not to nit pick, but most of Europe (i.e., other than Ireland, Portugal and the UK) is 6 hours ahead of the east coast, not 5. And if your flight to Europe from NY involves a layover, you are approaching a 12-hour journey... But a direct flight to JFK from Honolulu is less than 10 hours.