Z,
IMHO you can't get the effect of chipping the Shep Paine way that hairspray allows. If you are going to do just simple small chips and scratches, stick to his way. If you are going to do bold large area chipping (say Lebanese Militia T-55 or my Egyptian M4A4/A2 Fl10) you need to attempt the hair spray.
http://forum.ipmsusa3.org/index.php?/topic/14801-egyptian-m4a4a2-fl-10/&do=findComment&comment=84706