First of all, try to get two squads of them as soon as possible. Being at max range is also a must, they will gain veterancy considerably fast and once vet2-3 they will start shredding pretty much every infantry OKW can use. Try to always place them in cover or in buildings and take advantage of their camo. Also remember that if the enemy drops a weapon like a schreck or an LMG you should give it to pathfinders due to their higher shooting range range (after all just 2 men of the squad have the sniper rifle, which is the real dps source there).
A replay here of a game I played vs USF where my opponent used a different strat (that still involved pathfinders and a lot of infantry):
http://www.coh2.org/replay/26235/insane-back-and-forth-on-langreskaya
