an advice

canoeing is likely just the heat ~30C it can do it but may not look the prettiest.

Yup just keep raising the lamp to your recommended veg height from your light manufacturer. Sometimes you can lower them a bit more and be ok. 🤟😜

20 cm is pretty close. You maybe ok at that height but are more than likely going to stress the plant. If you place your hand plan side down over the top colas, do you feel your hand warming up? If so, 12 hours of direct light like that can stress the lady out. Also it’s your first two weeks of flower expect height to be increasing up till your fourth and even 5th week of flower. If you can tie down the tops abit to get 30 cm of clearance id do so. My plant in my current grow shot into my led over night and has taken some burn and heat stress because of it. Take a look at my flowering weeks 4/5/6 to see a concrete example. Good luck and happy growing.