[Cone Basher]

The boot should fit tightly around the ball joint. Once you have it assembled and set at ride height feel the boot as you add greese and stop once you feel the boot tighten or you will blow it off of the ball joint. If the boot is very tightly seated you will either blow a hole in the boot or see grease cone out around the shaft which IMHO means to much has been added. The purpose of the boot is to maintain a slight pressure on the greese as it works its way around the ball, as long as the boot is firm the greese is going where it is intended.
PS I've blown out a number of boots over the years and once you do this the boot needs to be replaced to work properly and it is usuall a PITA to fix.
HTH
CB