Please answer this question its urgent

Fashion-4-U is a rapidly growing manufacturer and exporter of ethically sourced fast fashion. It has recently obtained two new retail chain customers in Mexico City, Mexico. Both have agreed to use Letter's of Credit to finance the transactions. The first customer has selected an Advising Bank that the Exporter is not comfortable with. The second customer has chosen an Issuing bank that is not financially stable. Fashion4U would like maximum flexibility to deal with other banks and more security that it will be paid. As an exporter, what arrangements or changes to the Letter of Credit should Fashion-4-U request?