By default, dynamic and bulk share will share all fields available in a table. There are times when you want to control the number of fields being shared from your ServiceNow table. By specifying a UI Form View in the definition for Dynamic Share or Bulk Share you can limit the fields to only those that appear on the form view that you have personalized. See Personalizing Form Views in ServiceNow
Using Form View to restrict fields does not make sharing data run faster, rather it is slower because more work needs to be done to remove the fields you don't want to share
The dynamic share example below shows using the Self Service (ess) Form View for Incident to limit the sharing only to the fields in that view.
You want to use the actual Form View name, not the Title for the View Name value. For example, use ess instead of Self Service.
The example below show the same view being used in a bulk share.
The number of records returned in a view is based on the glide.db.max_view_records system property. Bulk shares of any views that have more records than this property will only be able to share this number of records and because of the way ServiceNow stores records, you will need to specify a condition on the bulk share to query based on a field that you know will not be empty on all records.