In your case I would take all the line fussing out of the equation. Make sure you use a holding blind while training. Walk from the holding blind to the line already lined up, say sit, dead bird and back. These high momentum dogs are usually pretty good at lining out there if you sit them with their head and spine lined up correctly. If he goes off Lind, handle from there.
After a while he will get used to running blinds a may relax a bit. Your instincts are correct, this is anxiety related to all the fussing trying to get that perfect line.