For those that reload for subsonic 9mm what velocity and bullet weight combinations are you using? Are you trying to achieve minor power factor? I am a non competitor, but want to shoot my reloads as close to minor as possible, yet achieve subsonic. I am shooting 115gr Blue Bullets over 5.8gr of Unique. The velocity should be about 1100 fps ( I have not used chronograph on the load just extrapolated from the load tables). The speed of sound is temperature and altitude dependent. I found this table and at the 2000 foot altitude I shoot, it should be subsonic.
Elevation - Temperature, Pressure and Speed of Sound.pdf