Streaming sunlight
 

I'm working on the pilot for a tv show and involved is a scene in which we do a classic snap cut of a sleeping character from night time to day time. To sell this we want the night scene to look like ceiling bulb and slight moonlight and the day scene to be sunlight through the window to the left and just some fill on the right to avoid harsh shadows.

As it's my first production with a budget and with proper lighting I'm still learning the ropes a bit and was wondering what sort of powered light I'd need for the through-the-window light. We'll have a hired fog machine puffing just enough to see 'dust' in the streams of light and using barn doors and other such devices we'll direct the light, but if we're shooting during the day indoors, what sort of powered light would we need?

I'm looking at hiring two 500W fresnels and putting them on stands outside, and then using a series of cheap 500W dimmed softboxes I've had for a while for fill, and as we're shooting on DSLR we should be able to bump the ISO up just a little bit and make the fresnels look brighter, but as I'm inexperienced I thought I'd ask those who've done it before, what's the best way to get that sunlight effect.