First time out...... had some issues...... make some tweaks...... go back and try it again.

Rear tire diameter?

If that 5900rpm is accurate for the finish line, with a 28” tire it shows 13% slip, with a 27” tire it’s 9%.

Neither of those numbers is great for a 10” converter.

I don’t think I’d make any type of combination changes until you have the tune/fuel supply situation really sorted out.

I’d set the camera up so you can record the tach during a few passes.

Some cars/tanks have more control issues than others.
My suggestion was to install a hydramat if running the fuel level up around 1/2 tank doesn’t cure it.