By the condensation it appears to be high. What's your calibrated hygrometer tell you?
It's such a small space the moisture coming from the eggs may be all you need. The humidity in enclosed space is adjusted by surface area of water not volume. Why in my full table top Hova bator (holds an auto turner) a double shot glass gives me 35% and a coffee cup and shot glass together is enough surface area to give that space 70%. Just play around with sizes to see what's going to give you 70% for last three days of hatching. I'd bet the eggs alone will keep it around 35% as they are larger duck eggs and its a very small space.
Of course the humidity in your house will be a large factor too. In early spring when hatching I need a humidifier just to keep the house comfortable from dry heat so that's one reason my incubator doesn't need much surface area of water to get desired RH.