Lights

24 inches = seedlings 18 inches = veg 12 inches = flowering. Yes, full strength the whole way.

Beware of phone apps. The sensors our phones have to view par doesn't take into count certain wave lengths. So your parr reading will be lower than your light may be. My manufacture provided me a parr chart for the light. If you can't find that i would do a broad search using chat gpt even to get an idea of what its capable. If that fails your only other way is to get a parr meter which can be pricey.

Get app tent buddy measure your par adjust accordingly

they tell me the tops of the plants if the apical one bends or doesn't grow I raise the lamp a bit... during germination height is more important than strength in practice, the first week a bulb a bit more powerful than the normal ones would be enough you can also see the distance with the elongation of the stem if the stem stretches bring the light closer at a certain point it stops and that’s the right distance

Depends on your output buddy. 400ppfd for seedlings. 4-600 for early veg 6-800 for later veg. And 800-1000+ ppfd without Co2. These are the nums you need to be hitting throughout your grow. Where you got your light. They should have a chart with similar numbers. And will tell you what %/height to have it set at As all lights are dif. But gen you want to be 45cm away. And with a 240w light. You shouldn't need to exceed 70% for your whole veg, "getting to that % gradually". Keeping 100% for flowering and dropping to a height of 20-30cm depending on your light.