The fact that you need to create custom app packages leads me to believe you will need Jamf Pro. In addition to packages, 60 computers will be much easier to manage with Jamf Pro because you can create set and forget workflows with Smart Groups.
Agree with the above poster. Not an expert on Jamf Now (although I use it to manage my personal devices), but for me the tipping point is probably around a dozen to two dozen machines. Once past that point, I think you're going to want the "Pro" features to make life a lot easier.