I have the greasable moog endlinks. My question is about the grease fittings, I can screw in, easily, 1/2 way by hand then it gets real tight do i use a tool to complete installation or should I keep trying by hand to fully install the fittings? Ive never handled any type of grease fittings and I dont want to damage anything.

 

They're usually a tapered fitting, so it gets harder the more you crank them in.
turn them in by hand as far as you can, then use a wrench or socket to put anohter little bit on them. don't rip them apart, but you can usually get another turn or two on them. just get them to snug up so grease won't leak out around the threads or that they'll come loose and fall out.