Fuel sender calibration

The only sender you might adjust is the fuel sender but if the arm is hitting the travel stops now, bending the arm wont make a difference at full. Senders areb't supposed to need calibrated.
Rather than crawl under the car just yet, try this.. Fill it up and check the resistance with an ohm meter. You can pierce the wire insulation in the trunk or remove the left kick panel to access the wire at the harness connector there. You're looking for 10 ohms, no less than 9.6 ohms. If you do see 10 ohms there and the gauge doesn't report full, the gauge is at fault.
If you see more than 10 ohms resistance the gauge wouldn't report full. The fault could be the ground strap at the sender, the wire connection(s) and lastly the arm not traveling to its stop.
There are threads here concerning incorrectly built aftermarket senders too. I dont think bending the float arm is the answer for that either. Good luck