I keep my light as high as possible in my tent. I use a luxx 645 led pro. I veg at 40% and just slowly increase the light till about week three of flower when the light is finally up to 100%

I think 1000 ppfd is the limit you want without CO2, you can download an app and it should be more accurate than eyeballing it.

Also, the light manufacturer should have some info about the ppfd of their lights.

But if the plants are rockin right now, I wouldn't do too much to change the light.

Be careful later in flower with a powerful light being too close to the buds.