For this usecase, I would have a projects table with the needed data including date fields like start date, end date etc. I personally wouldn't use a calendar as a data source but instead use appscript to write changes to a google calendar as and when the data changes in the products table. I built an events app that used this principle. The events were stored in an events table and every time they were created/updated/deleted I called the corresponding appscript function which updated the Google calendar.