The show schedule for the following month is pretty much always posted the last week of the current month. So March's schedule will be posted the last week of February. Aprils Schedule will be posted the last week of March.
I can tell you from experience, if your going during spring break (10:00pm Park Closing) there will be the maximum number of shows for each show. So a shamu show should have 7 shows during the day. Blue Horizons will have 6, Alure will have 5, Clyde and Semore will have 7 or 8 and pets ahoy will have 5. That may or not change do to crowd size that day.
The other option is the 7:00pm park closing which is also the time the park closes on some days in February. So they usually keep the same time slots for each park closing time. So according to the February 7:00pm park closing schedule for the weekend only, this is what you can expect http://www.seaworld.com/ParkHours.aspx?LocationID=1&ScheduleID=40237