Just wanted to chime in as someone else who flies long haul pretty regularly.
You can get used to the time change and develop your own tricks to minimize jet lag. So a lot will depend on how experienced your MC is with this kind of flying. I barely get it anymore in either direction. I'm tired for a day or so, but just traveling will do that to you.
My last long haul was W. Europe to Japan, had almost no jet lag when I got there, and flying east is usually the problem direction. My trick is always setting my watch to the time at my destination right when I get on the plane. When they're serving dinner, I'm thinking about what time it is in Tokyo (or wherever) and eat accordingly, maybe only lightly because it's the middle of the night where I'm going. For me regulating time to meals is a biggie. I also definitely try to sleep when flying east, even if I only manage a couple hours. Flying west, I stay up the whole time. If I know it's going to be a 35-hour day or whatever, then ok. You can mentally prepare for that.
I've flown transatlantic with my kids, both when babies, and that was another can of worms. When I flew Europe to USA with my 10-month old, I had the worst jet lag ever because she *never did the time change* for our entire 8-day stay. So I didn't either. Ugh. Don't fly with babies.