I am planning on fastening the roof trusses of my own house directly to the concrete with a Simpson Strongtie LTA1 or HETAL. Those connections provide a slight separation so the wood truss is not in contact with concrete and provide 1000 to nearly 2000 pounds of uplift load. I will attach 2x scraps to the brackets and set them in the wet concrete to the truss layout and set to height with the laser.
What have others done?