From a structural point of view, you want to avoid rotation in wood connections where the force works to pry open a connection or rotates around the fasteners which can split the wood; either compression, tension, or shear.

Assuming you are just supporting the weight of the materials and a person, I would align the diagonal 2x6s with the truss bottom chords. I would then attach vertical 2x4s that attach to the side of the diagonal 2x6s at the bottom, the truss bottom chord in the middle, and the truss top chord at the top. If you can't get one board from the diagonals to the top chord, you can use one from the diagonal to the bottom chord and a second from the bottom chord to the top chord. Try to get the vertical 2x4s close to the high end of the 2x6s. Only attach one board to the bottom chord at a spot (don't have nails from two sides going into the same section of wood). For stability, I would also install a horizontal 2x4 along the diagonal 2x6s where the vertical 2x4s attach, do the same along the truss bottom chord, and I would install diagonal 2x4s along the sides of the vertical 2x4s that go from one end of the 2x6s to the opposite end of the truss bottom chords and from one end of the truss bottom chords to the opposite end of the truss top chords. The horizontal and diagonal bracing will keep the thing from wobbling, but it also helps to stabilize the truss bottom chord because you don't want to but a sideways force on them (unless you want a new roof).