As a ward executive secretary in the past I used a Google Spreadsheet for each month, than shared it out to the Bishopric -- that worked pretty well, but last year I was called into the stake as an executive secretary, and we have been using Google Calendars, It has been a lot better in my opinion.
I'm using Calendars by Readle App for IOS on my iPhone & iPad as the client app for accessing and editing the calendars, it makes it real easy and quick for scheduling and managing the flow of interviews & meetings. I prefer to keep my church and professional calendars in separate apps.
The calendars are shared to all presidency members, and we have several assistant executive secretaries, it keeps everyone on the same page and in sync. We also created a temple recommend calendar (in Google Calendars) it is linked up to an online service called
http://youcanbook.me - We set up the open availability, and the tool automatically books the person or couple and puts the info on our temple recommend shared calendar. We put a link and QR code for it in all of our ward bulletins. It works great!