Regarding timing for submitting the application for 60 Days Extension, my current Extension of Stay expires on 5th Aug, and for Annual Extensions I would typically apply 30 days before expiry, however, for 60 Day Extensions I assume that applying a few days before 5th August should suffice?
In fact the non-resident tax rate is worse than the 30% flat rate that was mentioned above. It's currently 32.5% on income up to $87K, and then a higher rate of 37% kicks in on income above $87K.