Compressing snare

So I was able to gate my snare to prepare it for auto replacement. However, I'm trying to get rid of some of the dynamics of the performance before doing the replacement. There are a lot of weak hits and then hits that are too loud. I can't seem to get the compressor settings right to squeeze it. I have the attack set late and the release set high the ratio set at about 40:1, but I can't figure out where to set the threshold or the gain. I keep compressing and nothing happens to the track. What am I doing wrong? Also, should I use the regular compressor or the one that's attached the the gate?