replacing shocks

I bought bilstein front struts, i installed them, after installing them,did a test drive and the shocks was making noise, it was loose on the top, center bolt. which i held with a wrench and tightened with an Ln wrench, is that the right way to d it, i am not sure if i did it the right way.after i tightened the center nut its not loose anymore, but i dont want to over tighten them or too loose either,,.also the rear shock mounts came without the shock mount gasket, is it have to be there. or can i replace them without the gasket..please help,kinna lost case here,thanks..