[Marshall V. Daut]

In your first two photos, it doesn't look to me as though the clutch pedal has been pulled all the way to the back of its travel. Either tie it there or have a helper hold the pedal in its rearmost position. Then line up the trunnion hole with the clutch release arm.
I always have to use a wooden block underneath the clutch arm and jack it up so that the clevis hole will line up with the clutch release arm hole for the clevis pin to be inserted. You cannot do this by hand unless the trunnion is way out too far. The higher up the trunion is screwed into the threaded trunnion nut, the higher up you will have to jack up the release arm. If you have run out of threads on the trunnion shaft, something is wrong with the clutch adjustment or the clutch fingers have collapsed.
Marshall