Filling the shocks should be in your manual, but what you're shooting for is to have the shocks filled to the point that they just about spill over when the shaft is compressed all the way. (Without any air bubbles, of course)
I have done and redone my shocks many times. The savage shocks are a pain to get all the air out and keep it out. The top of the cap holds an air bubble that is difficult to compinsate for. On a basher it is not that big of a deal. If you race you propably use other shocks anyway.
Easy way to tell if your right is when you have the cap on the shaft will go all the way in with out resistance and push back just a little, about 1/4 inch. If theres no push back its too low, if there alot of resistance, or you cant push it all the way in there's too much. What wgt oil are you using?