John Rodrigues M3*H30 would be ideal.
I’m also planning to use this with the TJC drone to connect the fishing hook release mechanism. In the space created by the standoff, we can place the battery to balance the quadcopter. Usually, people place the battery on top of the quadcopter. This makes the quadcopter roll to a side (moment about CG). If it’s below, the same moment will try to level the quadcopter.