I think charging about 1% or even half of that per transaction on Hive-engine is really high. This can discourage high level traders from making multiple onchain transactions, plus large single transaction would cost alot in fees. For example, 1% fee for a million dollar transfer would be $10,000. That is outrageously high. The fees should be very low so that it would only cost probably about $10 (or less) to make one million dollar transfers within Hive-engine, which would be 0.001% in fees. While fund withdrawal may cost alittle more.
Fees generally should be insignificantly low to attract alots users of different economic classes especially those with large funds, to Hive, and greatly increase onchain transactions on Hive-engine.
And Hive-engine should be very decentralized and secure to make this even beautiful as if you are trading and keeping funds on centralized exchanges, but with 100% control over the funds.