Welcome to Smogon! Take a moment to read the Introduction to Smogon for a run-down on everything Smogon, and make sure you take some time to read the global rules.
4 pm +5.5 is definitely acceptable, I have variable timings so you will have to either wait a little or wait from like 2 pm your time. I'd be comfortable if you did it even earlier but its all on you
(Fyi I am not available from 4:30 pm your time i.e. 1 pm my time)
I think I wont be able to battle for today until further notice due to an exam, dont try to call act because you said you would be available from 3 pm your time