First, that is one sick nova!
I have a 70 only hope to aspire to have one as nice as yours! Its just my humble opinion but my first reaction was that the booster is way to small, which looks like you came to the same conclusion. Also in regards to the bubbles, you might want to try to re-bleed the master. Sounds like the master still has air in it. I had the same issue on my buddies car where he thought he did a good job of bench bleeding until we put in the car and mushy/too much brake travel. Turned out he could not overcome the spring pressure by pushing with a screwdriver and only bleed half the master. I just rehooked the bleed kit up with it installed and had him push with the pedal slowly until all bubbles were gone and that cured it. Dont know if that is your problem with air bubbles or not just thought i would throw that out there. btw: i would love to see more pics of it, interior as well. nice job.