Schedule Tweets on Google Calendar
After installing this Applet, create a Google Calendar event on the calendar that IFTTT is watching. Set the event time to be 15 minutes later than when you want the tweet to be live. (IFTTT's Google Calendar triggers happen 15 minutes before the actual event.) Put the Tweet Keyword (eg. "#tweet") either in the TITLE or the LOCATION of the Google Calendar event. Put in your actual tweet in the Google Calendar event's DESCRIPTION, keeping in mind of Twitter's character limit. Watch IFTTT work its magic and tweet for you!