You can control the number of columns and rows in LaunchPad. To do so, edit the com.apple.doc defaults domain with the key springboard-rows for the number of rows to display and springboard-columns to control the number of columns displayed. So to set the number of rows LaunchPad will show per screen, send the write verb into defaults for com.apple.dock along with the springboard-rows and an -int of 4:
defaults write com.apple.dock springboard-rows -int 4
Likewise, to set columns to 8:
defaults write com.apple.dock springboard-columns -int 8
Then just killall for Dock:
killall Dock
In some cases you will also need to send a resetlaunchpad boolean into com.apple.dock (for TRUE) along with a killall for Dock (or reboot):
defaults write com.apple.dock resetlaunchpad -bool TRUE; killall Dock
