Have extra calcium too. Oyster shell is perfect. Phosphorus at 160mg per day per os per bird will be good.
(And I just worked out what BLK AUS means ha slow).
As for egg mass, make sure protein is up to scratch (see what I did there?) Make sure the amino acids are all correct. Grab the requirements sheet for australs. I know how hard it can be in Aus to know exactly what amounts of anything are on anything, as much as they love to charge you a mint...