Look into the Armstrong or Ranger Recon Pullup program. If your programming doesn't fit either of those, then do GTG PU.
Use 50% of your max for 5-10 sets a day.
According to this http://www.leatherneck.com/forums/sh...94&postcount=2
you might want to do 100 pullups throughout the day.
10x10 isn't gonna happen by 15x7 or 20x5 sound maybe doable.
After waking up, before sleeping, after breakfast, after dinner, when getting home, midmorning, afternoon, evening, before dinner, 2x while at work and school. You may have to do 2-3 sets per occasion.