I'm a lazy old fart, so once I'm in veg, I set my lights as high as I can, and turn them all the way up.

That way, as the plants grow and need more intensity, they're getting closer to the light. And thus getting the more intense light.

 May not be "optimum", but it works well, and it takes a lot of worry out of my lighting.

700 watts, in a tent??  WOW

I'd hike the lights up, and put your light at 50%, for now. That's where I'd start, and adjust power (not height) from there.

But that's just me, and like I said, Ima lazy old fart.  lol