By my personal experience, I would suggest better to go for total de-roofing of the pulp wall and complete removal of coronal pulp in children with asymptomatic deep carious primary tooth. Again the same instrument is handy in amputating the coronal pulp.
I think partial pulpotomy is more indicated for a traumatically or carious small and recent pulpal exposure, in young permanent tooth especially one with an incompletely formed apex. For completely formed primary tooth, amputation the entire coronal pulp is suggested. Removal of the pulp tissue by using a slow-speed round bur No. 6 or 8 or sharp spoon excavator.