It is possible to link Custom Properties to balloons in a SOLIDWORKS Drawing Template without editing each balloon.
After a balloon is created, Custom Properties can be specified as Balloon Text values from the Balloon Properties panel.
The default text for a balloon can be set to a Custom Property too.Refer figure below.
You may access the Property List from File > Properties and then select Edit List.
Before linking balloons to custom properties, do make sure that the Custom Property must be added to the Property List and defined in Document Properties. Once done, save as drawing template.
Take note that the parts must have the same Custom Property.