By the time you are finished, there won't be any smell.
But, you should treat the tub with phosphoric acid, maybe diluted, and then rinse. The 2 911s that I did extensive work on got acid in all the concealed cavities, rinsed, dried and treated with various anti rust compounds ranging from cavity wax to POR 15.
The cavities were also cleaned as well as possible with air pressure out of a long nozzle and vacuuming with a skinny hose.
I can't imagine any smells other than the new leather when finished.