RE: Air bubbles
Remember that the difference can be VERY subtle.
In one case I had something similiar as what you are experiencing occur.
It seemed to occur the most in uplines and when accelerating, but I could not explain why for a good while...
It turned out that the fuel tubing I was using on my replacement tank was stretching due to the G forces involved. I had a standard clunk in the system at the time...
It was bottoming out when the plane accelerated, leaning out the engine to the point of cutoff...
I found this almost by accident...
You must have changed the tubing, fittings and lines, so things are not exactly the same.
Since you state that bubbles tend to form the most at full throttle, it may be that with the higher pressure, air is working it's way around the fittings. Consider putting wire ties, etc. around the tubing where it contacts the fittings to prevent this.
Check to see if bubbles form at full throttle with the tank completely full. If they do, you definitely have an air leak... probably at a nipple.