Create ~/.xsessionrc for quick session changes
Since ~/.xsessionrc is activated by xsession why not use it ? Just create it in your home folder and use it to make quick settings to X. Here is an example of mine:
# turn off default screensaver
xset s off s noblank s 0 0
# Set mouse accelaration. Works before LXDE takes over. To change final setting edit ~/.config/lxsession/LXDE/desktop.conf
xset m 5/2 4
# Set gamma correction
xgamma -rgamma 1.05 -ggamma 1.15 -bgamma 1.136
# Load monitor ICC profile
dispwin -d 1 ~/.config/color-profiles/IBMTPLCD.ICM
# Start xcompmgr
xcompmgr -a &
# Start clipboard-daemon
clipboard-daemon &
# Start keyboard layout switcher
setxkbmap -option '' 'us,bg' ',phonetic' 'grp:alt_shift_toggle,grp_led:scroll'
# Enable key sequence to kill the X server. Old behaviour
setxkbmap -option terminate:ctrl_alt_bksp