1. Fees are fixed, 3% for large transactions and 5% for small transactions. This is higher than many since we are privacy oriented.
A trusted competitor service I have used many times also charges a 5% fee for bitcoin to monero transactions so I can't really complain about that. You should state what you consider a small and what a large transaction, though.
What can you tell us about your reserves and holdings? I think your potential customers should have a way to check if you have the coins you claim you do in your possession.