A synthetic isn't truly necessary for anything but piece of mind on a Huasheng. Take azbill's HS for example, he put over 14,000 miles on his engine using nothing but conventional 10w-30. No fancy synthetic or heavy duty oil, just regular automotive oil. It's easy to overthink things when it comes to oil, and many people have their own opinions on the matter. That said, friends don't let friends use Pennzoil!
I've experimented with a number of different grades on my HS, from straight 30 to 15w-40 and 5w-50 full synthetic. I've been using
Shell Rotella T for the last 3 oil changes. It's a conventional extra-heavy duty oil that came highly recommended by a friend of mine who rebuilds a wide range of engines for a living. He thinks synthetic oil is a gimmick, for what it's worth and won't dare to use it on his own engines. All he uses is Rotella T.
In the end it may or may not matter what you use, so long as you change the oil often enough. I change mine every 6-10 weeks.