This. It can be easily done in the GUIs as well (Don't ask how I know). I don't know where GP got the idea that you can't set a client to 0B/s. All the clients

This. It can be easily done in the GUIs as well (Don't ask how I know). I don't know where GP got the idea that you can't set a client to 0B/s. All the clients I am aware of support setting the seeding rate.