It all depends on the salary range you are looking at and how much you pay for child care. I know when I did the calculations my take home would be the same whether I did 5 days a week or 3 because of the childcare rebate having a maximum threshold. This is based on earning too much for to get the Child Care Benefit or only very minimal CCB.

I haven't found a decent calculator to be honest that takes everything into consideration, but you can do most of it using the family assistance ones for calculating CCB and CCR and just vary the figures you put in. So first do for scenario 1 - then scenario 2 etc - and note them down and compare differences. This doesn't take into account tax implications though.

I am considering full-time but only because I can't seem to find part-time - it doesn't give me anything financially.