It could help to know what type of incubator you have. It's quite possible in Australia it's one I've never heard of.
Humidity can be rough. Different humidities work for different ones of us. You'd think that inside the incubator conditions woulde be the same for all of us but that just ain't so. Some of us have forced air and some still air. Living at different elevations means different air pressure which can make a difference in what humidity we need. We have different background humidities at different seasons. I can get a 15% difference in humidity inside the incubator doing exactly the same thing but with different background humidities in spring versus summer.
Don't get frustrated. You don't have to hit humidity dead on. As long as you are close you will probably do OK. For me, 60% does seem high and I'd try to get it down like you want to do.
Other than backgroud humidity, the humidity is controlled by surface area of the water. This is for those that have reservoirs in them where you depend on evaporation. There are some that handle it differently. I don't know about them. Mine is a Hovabator 1588 and has 5 different reservoirs in it. Different reservoirs are different sizes. I control humidity in two ways.
One is pretty obvious. I fill different reservoirs. That's the easier one.
Remember that surface area is what counts. If you need to increase your humidity, if you add a wick to the reservoir, like a wash cloth, the water will wick out of the reservoir and you'll have a bigger area for it to evaporate. But that's not what you want to do. Try covering part of the reservoir with aluminum foil (Probably aluminium to you). You can use something else as long as it does not absorb the water. Or float something in it that does not absorb the water but will reduce the surface area.
It sounds like you are just starting. Don't freak out. You have plenty of time to get it right though a good time to start is now. What counts in incubation is the average humidity over the life of the process. Over 18 days the chicken egg needs to lose a certain amount of moisture. Until you go into lockdown and the eggs start to pip, it does not really matter if the instantaneous humidity is 70% or 15% as long as the average is pretty close to what you want.
Good luck!