I'm at Logan Village (not Logan Central) near Tamborine Mountain in SE Qld.
Sounds like you have set up your hives very well. I know the president of my local bee club (which meets at Sunnybank) uses oil. I don't, as I guess my hands are too shaky. LOL. Also I don't have much use for the discarded oil, but I can use the hydrated lime in the garden.
Thanks for letting us know, the oil catches ants too. That's one good thing about the oil, that I haven't noticed with the hydrated lime. I do find wax moth grubs in the hydrated lime from time to time.
My modified bottom board uses a propolis mat, which covers the whole bottom board too. It is only about $10 from my local bee supplier and is the right size; doesn't need cutting.
Balls of pollen are usual. Some pollen is knocked off when the bees walk over the propolis mat, or mesh in your case. I've checked the brood box and they still have plenty of pollen in there.