Only one way to find out. Turn off everything, and I mean everything, in the house but one strand of lights. Monitor the meter ( might take a week to get a reading ).
Do this once with the twinkles and once with the steadys.
Report back to us in January and let us know the answer.
;-)
No, you got it all wrong.
They need to just stand at the breaker panel and flick the main on and off maybe every 2 seconds. They'll save on the total light bill that way.
I hope their lights ain't chasers....