Personally, I don't think boys have much prospect as production clerks. The production clerk is nothing more than the statistics of production reports, similar to ordinary clerks. Moreover, there should be very few boys working as production clerks, and the working hours should not be too long: one day at most 10 hour, and an extra day on Saturday is also acceptable. Different companies have different requirements, the salary is generally around 1500, and the total overtime should be around 2000.
In addition: I suggest that if boys want to enter the factory, they should still look for technical or business jobs, such as engineering, design, commerce, supply chain management and so on.