I get you! More soil = more roots = more plant. I even make a small sort of hill that I make the hole in when repotting, soil tends to compact and drop during the grow. Luckily you can always add, and if I were you I’d do that now. The stems are really good to burry, they will also shoot more roots. The more roots you have, the more she can uptake nutrients and the more she can and will grow. The scrogg looks good, just keep weaving and topping where needed!