Search out "DSDtune", run it and after a few moments of it opening and closing it will display optimal settings for your setup.
My input/output settings wont be the same as yours (you listed "-i2 -o1" as yours).
The "-f1" looks right for our area as that is enabling P25.
The DSDPlus readme will tell you all about the variables...
https://pastebin.com/4FbWtbKm