A while back someone posted about the random length of leader before VV actually starts to playback a project (when manually outputting to tape). I'm seeing the same problem. It's really annoying when trying to make a VHS dub to have so much dead space at the head of the tape or to wait a little too long and miss the start of your project and have to start the process over.
But I came up with a simple workaround. I started placing a 5 second "Roll Tape" text / background clip at the beginning of the timeline followed by 15 seconds of black. That way I can just watch for the "Roll Tape" prompt and start my VHS tape right it goes to black. Now I can get consistent dubs.