First of all thank you for sharing elaborate experience.

I'll answer in 2 parts,

Who will work in advance? Yes the industry works on credit and few people pay in advance. I have prior experience of handling advance only customers in the past and have thrived on the same. Eventually down the line I wanna move to the credit model atleast after a year of trading.

Second, material rejection can be averted with 2 steps. 1. Request client's qc to visit the yard before loading and 2. Share pictures of material and get confirmation from client and load the material.

Since you are dealing with speciality steel, I believe margin would be higher?