No worries bro!Haha. I have an ongoing grow thread linked in my signature down there that you can flip through. My largest auto plant in that thread was 22oz. These days anything under 16 bums me out.
How? Dunno. I like to see how hard I can push them. But I know when to back off. Good lighting and environment. Plants are plants. Lots of experience growing other plants before I had even thought about growing canna.
IMHO, no magic bullets. But no secret either. Let the plants tell you what they want, need or can take - observation. Go from there. Over time you develop a method that works for you and remains "consistent" even with Autos. Once you find consistency, you can tweak and see where you can improve, or not.
Anyhoo, not trying hijack the thread. My original post was to offer encouragement. Just wanted to answer your question. Good luck.
Feel free to post whatever you wish here. Always appreciate good input and advise.