Hi itme,
That sounds reasonable to me. I didn't see a current specification for the green power on signal either but i would expect it to be only a few milliamps. To be sure GND it through something like a 100 ohm resistor, check if the supply comes on, and measure the voltage across the resistor. Current = V / R.
The SSR looks to be plenty adaquate to me.
HTH
Regards