You really did not need to add blank or black video to space the source clips as you wished.
You may have needed one long blank video ( eg Black or Transparent) to set up a sequence of the require duration though.
Do that on a separate track so you can delete i in one action and dont need to eliminate it between the clips
Might have saved some effort and time.
Hopefully you discovered the methods to manually enter a TC in the BOX and the play head jumped to that position in the timeline.
Ganging Source and Program Monitors may also have been an aid.