My method for testing miter setup with a table saw can easily be adapted to the track saw.
Start with a sheet of 3/4” plywood about 13” x 10”.
Set your saw at a nominal 45 degrees.
Cut the 45 degree setting along both of the 13” long sides.
Cut four (4) pieces 3” x 10” from the mitered board.
Lay the four pieces so that all the longer sides are facing up with all the 3” edges touching each other.
Using heavy duty pacing tape, tape all the mitered edges into one long strip measuring 3” x 40”.
Fold up and tape into a square.
Observe the miters. If they are tight, then you are ready to start. If not, tweak the adjustment and repeat the test until you get a satisfactory result.
This thread deals with the same subject. My post (#15) illustrates the above in photos. And it seems you have posted there in the past.
FWIW...I'd consider going with a lock mitre joint, it's what JBL has been using for the last 50 years and is acoustically preferred because of the additional glue surfaces. The additional glue surfaces prevent material separation and prevent potential resonance issues.
I think Totem Acoustics does that too. I have an OF1010 router but have not invested or made a router table yet. Maybe next go around. I am just going to use dominos and glue this go around.