Regarding rollover I find the best way to look at it is this:
HSI rolls over on the day before the last business day of the month. That means that late in the afternoon the current month will stop trading. If you watch it you will usually get reasonable movement in the morning but it will flatten out after lunch. So you could trade the current contract in the morning of the last day if you really wanted.
I find that the volume on HSI isn't higher in the new month until the morning of rollover day. So now I trade the current month until the close 2 days before the last business day of the month (ie close of day before rollover day). Then on the open of rollover day I start trading the new month.
HSI rolls over on the day before the last business day of the month. That means that late in the afternoon the current month will stop trading. If you watch it you will usually get reasonable movement in the morning but it will flatten out after lunch. So you could trade the current contract in the morning of the last day if you really wanted.
I find that the volume on HSI isn't higher in the new month until the morning of rollover day. So now I trade the current month until the close 2 days before the last business day of the month (ie close of day before rollover day). Then on the open of rollover day I start trading the new month.