Hmm...
I think you shouldn't lock yourselves up in certain positions, as you might find it boring always playing the same way - But as you state it seems he would be a good supporter (read back or snake-player - 2 very different things)
A couple of years ago I would say Shocker - today I'd say Shocker, Electrococker, Matrix or Impulse... Or how about just choosing a marker that he likes and has little of everything??
I use the Impulse as a back or midfield and it has everything including nice consistency and good airconsumption (Front or back doesn't matter with this marker)!! With just a new trigger it can shoot as fast as any other marker - I find it very reliable, good as standard but also very very good upgrades and it rarely breaks (just grease and change battery)!!
You should try some other markers as well, but the "Impy" you must try...
Pinky, Team Wikings