I used to lst my plants but in the end I didn't like it especially if you let your plants get some height on em they are gong to be super flimsy. I like to top my plants when they are a little smaller then yours. Then top those tops then top the side branches that reach the same height as the...
On the cracks that don't need to be open use some flexseal it works great it turns to rubber when it's dry I use it to light proof my window and ducting going outside.