Hi,
As you have mentioned you can set the granularity to one minute. Why do you think that you cannot use this approach?
You can use the graphs which are available in Analysis and make some adjustments.
In this case you can set the granularity to 1 minute and change the name of the graph. You can also change chart title and chart Axis title to Hits per Minute using Display Options -> Advanced...
I hope this helps.
Kind regards,