Hi mjim, I trade time spread, I have a monthly strategy using SPY. When you trade option strategy you need to follow the evolution of the t+0 line by using the expiration graph a very good tool is the TOS platform, you can create a demo a account and start using it. The only issue is that it has a 20 min delay in the data, whit real accounts the data is real time, but unfortunately TOS(ThinkOrSwim) don't allow Australian to open accounts, you can create a demo account here:
https://www.thinkorswim.com/t/pm-registration.html