RE: Fuel Starvation?
During high "G" manouvers the clunk WILL pull on the fuel line causing it to stretch.
This can cause it to lock into the wrong corner on the rear of the tank briefly causing it to be out of the fuel, or to hit the back of the tank which permits a slower flow that leans the engine.
Add another 5mm's of distance between the back of the tank and the clunk.
Also use some mechanism to hold the tubing onto the metal feed through stopper tubes.... e.g. I often use wire ties INSIDE the tank.
Are your fuel lines SHORT? If there is a semicircular loop anywhere, is there any chance it is being pinched off during high G rolls?