If so I have found seedlings= 13k-15k to start.
Step up to 20-25k 1 week in.
Then keep increasing light level as the plants can take it.
I have 4 plants 1.5 wks old under 45k Lux atm.
This is under 1000w HPS. I know Lux meters dont work as well for LED, but hope this helps some.
There are some Lux apps for smartphones that aren't too horrible btw.
This is 5 weeks old getting 75k Lux.
My last run ended flowering @ 70k Lux (lower power light) and I was able to get 2lbs from 8 autos on my first grow in a 4x4 tent.
Zman u need to get a lux meter...trust me and smoke on this. Guessing sucks.
I would start at 5 to 7k lux, smoke is pushing it for a new grower imo. Better to stretch a little than get light burn.
If your light can be dimmed it saves a lot of having to move it up and down. But if you have to run a true 1000w led above seedlings at full power i would guess you need to start at 40".
No need for lux meters ... or other crap . Simple distance heights for growth is easy. Most blurple panels “ actual “ pull is always about 1/3 as advertised. If your panels have separate “ bloom/veg “ ...always run both on. Use your hand as a metric to judge the heat intensity on canopy , hold over canopy , if still comfortable after 15 seconds , then you are fine. Seedlings CAN be overwhelmed by these panels due to the “ intensity “ of focused light. You can always pre “ harden “ your young plants with a flouro lamp like T5 ( running close ) to get them ready for more intense light systems too.
Take the Flowering distance with a grain of salt ( distance ) .... 15” - 18” seem better to reduce stress and bleaching.