How high should we have our 1500 watt LED lights from the seedlings during germination

A customer has a question and I hope we can get some opinions on it, thanks

How high should we have our 1500 watt LED lights from the seedlings during germination and then vegetation stage?

The germination process should be done in the dark.1500 watts is intense for a sprout. I have 1800 watts and I keep them like 35/40 inches above and lower them slowly over a couple weeks. And usually keep them around 20/25 inches above after that. But you can play with the height. Just watch out for heat stress and yellowing leaves.