Buying copper cathodes, 30000 mt monthly, CIF China

We would like to buy copper cathodes 30000 mt per month, CIF Shanghai port China；
100%LC released at destination.
We have requirements as below:
1. The supplier's LC receiving bank is a bank in China, we only accept LC of CNY.
2. The seller provides past transaction records with the Chinese buyer（if possible)
3. The supplier shall provide company information, previous inspection reports, videos and pictures (if possible).
4. the bank of supplier issue PB 5%,we received PB 5-6% rather than normal 2%.