Watched your video and it is VERY cool. I am impressed!
Since you are so good at woodworking. I think you can make switching bottles a little easier by adding a spring-loaded arm, like this one but instead of aluminum alloy you can use wood of course.
I bottled 200 bottles (cab franc, syrah) yesterday and have a group coming over today to bottle another 300 ( Rhone blend). It worked like a champ yesterday, although I'm noticing the air valve may not be opening all the way and there is some vacuum that stays on after the timer turns off. Not a big deal, but I'm thinking it could be because the valve is designed for fluid being pushed through it, versus air being sucked through it.
A wine neighbor stopped by, who helped a commercial winery the day before. He said my filler worked just as good as the filler at the winery (not sure type, but the winery does 3,000 cases per year).
Well, the bottler showed its inconsistency over the 300 bottles. It would do 5 in row fine then fill the next bottle up 75%. Most of the time it was due to not getting a good seal on the bottle being filled. I could manually fill it a little more, but not having to fiddle with the bottles after it completed the first time fill was the purpose. 500 bottles in two days was a pretty good task.
It got the job done, but really didn't operate to my satisfaction. I'll put it away until I'm ready to go through it and make it more robust.