I wish this helpful for you First of all, the timeout to configure in your case is OperationTimeout, which allows the time limit to wait for the service to reply before timing out. You can modify the operation timeout before making a call from the client side. To set the OperationTimeout on the channel, you can type case your proxy/channel instance as IContextChannel and set OperationTimeout.
IClientChannel contextChannel = channel as IClientChannel;
contextChannel.OperationTimeout = TimeSpan.FromMinutes(10);
How to change command timeout in pywin32. 'Open' method