Yeah every single game out there is different. You have to figure it out for yourself.
And melting card/blowing up PSU... won't happen. Or rather, if it does happen, it'll have nothing to do with your settings. GPUs won't overheat unless you never ever clean the heat sink, and the PSU well depends. 22A on the 12V should be sufficient tho.
if you concern about heat then just make sure your case have good air flow so to keep your ambient temperature at reasonable level. other than that you might want to make custom fan profile for your card using software such as MSI After burner. certain cards only raise the fan speed once the temperature hit 80-90 degree which is certainly raise your ambient temp