Re the cloud formation heights, as I mentioned I know the types of clouds and the staggered strata at which they exist. So unless the barometer is low low low there is no reason for contrails to form under a certain height or under certain cloud formations.
The video below is an example of the dilemma I find regarding the contrail/chemtrail truth. I have seen contrails at altitude and contrails at 10,000 ft as exampled here, which is unexplained. This video if genuine shows no clouds in the sky to speak of so we can surmise the barometer reading is higher rather than lower, yet the trail at lower altitude persists and becomes volumes.
I'm interested in how you determine the 10,000 ft figure here.
Consider that if two trails are both thin enough that you can see through them to some degree, then it's impossible to say which trail is higher. In front, or behind, the overlapping of the trails will be identical.