No one is asking you to click 100 times to buy 500 goods, please stop making that up.
Scale it up.
You want the maximum trade size to be 100. Then if I want 10,000 goods I need to take or post 100 trades. If I want 50K I have to take/post 500 trades.
You want the maximum trade size to be 500. Then if I want 50,000 goods I need to take or post 100 trades. If I want 250K I have to take/post 500 trades.
You want the maximum trade size to be 1,000. Then if I want 100,000 goods I need to take or post 100 trades. If I want 500K I have to take/post 500 trades.
Do you understand our objection to your totally unnecessary limit?