I'll let you know what has worked for me as I just got my Safari the end of January.
If you are hunting parks, I would opt for the Coin and Jewelry mode, or Coin mode. I like Conductivity Audio over Ferous, but thats a personal preference. There is a good video on the sounds on mlotv.com.
I now run my discrimination as low as I can stand and listen to the tones. I only reject -10 to -4, but this will drive you crazy if there is a lot of trash, but it helps with masking of good targets by junk.
Auto sensitivity works very well, use it until you get some experience, then try manually adjusting it.
Use the High Trash Density Setting.
Don't rely on the target ID, but listen to the sounds. If you are hunting trashy sites, the Target ID is going to try an ID everything. I have recovered silver where the target ID goes from a 38/39 and then down to the negative numbers. You will get low tones mixed in with the high tones. Sometimes it's just junk, but I have recovered silver this way.
I sweep at a moderate speed if not to trasy, then if I hear something worth checking out, I slow way down over the target with short sweeps and may have to check the target from different angles.
If the area is very trashy, I slow way down.
If I get in a spot where I am recovering some old coins, I slow way down and meticulously check the area.
Also, use the depth meter. This is one of my favorite things about getting a modern detector. It tells you the depth without having to pinpoint first. Once you get an idea of how deep the older targets are, once you hear a target response worth checking out, look at the depth. If it's deep, dig it. Last weekend the old coins I recovered didn't sound great, but they registered at 5+ inches so I dug.
I have used the depth meter to recovery lots of War and Buffalo nickels. Most tabs I find are surface to 3 or so inches. When I get a good nickel signal that reads 5 or more inches it's a good chance that its something good.
Hope some of this helps.
Dan C