This is my 2nd year so take what I say with a grain of salt.
That being said I came across more Tetramoriuums last year than I knew what to do with. I thought it may have been my location..but really I see them everywhere.
My advice is try and locate an already established colony close to your house. I've got....at least a dozen ant hits where the street meets the sidewalk. Not in front of my house but off to the side (more so my neighbors). They would be my queen source. Then it's just getting in a routine of "After a rain/early weekend morning (before the heat comes)" during their flight periods. go inspect things. I probably got super lucky by coming across 50+ in my front yard driveway whatever morning that was. I literally walked out in PJs with my coffee just to look....and there will sooooo many queens going from the left side to the right side. This was....June? I since saw them at my work, and even had one land on my windshield as I was driving to work. They are everywhere.
We are probably getting close to their flying times. I got my Tet-Queens from the flight off the ground, not from digging up chambers.
Though...Went on a bike ride to the library yesterday. Passed... 3 dinner plate sized mounds. Darn Pogonomyrmex's are already tearing up the fields! They are what I'm wanting again this time. Only got 2 last year and had accidents with a third.