4.4Ghz to 4.5Ghz? I'm afraid that you will see no difference. That's not worth the effort. Try the game (at 4.4GHz) and see how it goes.
Below 1.3v (with "medium end" air cooler) is safe for every day use. Stay below 1.35v. Stock voltage at 4.4Ghz is around 1.2v.
I run Prime95 (8-12 hrs min.) for stability when I overclock. I always overclock the CPU by the mobo bios.
No.
Install CPUID HWMonitor, and monitor your stuff. Vcore, Core clocks, wattage, etc.