144-hour visa with a Z work visa

I will be flying to Shanghai to look for an apartment for about 5 days. I am a US/British dual citizen. I want to just arrive 5 days in Shanghai to sortout my apartment before going to Thailand for two weeks. I will then return to Shanghai using a Z visa I will be issued to work there’s. If I don’t want to use my Z visa in my US passport yet because then I have to stay in the country for about a month before leaving. Can I use my British passport just for the 5 day visit? Then when I return after being in Thailand I will use my US passport with my Z visa in it. Is this ok?