I feel that's a lot of butane for what you got out of it. It's good to weigh it before hand so you know what you're yielding. Example, if you get 10 grams out of 2 cases of butane, then you aren't profiting, just turning it into something else. I was only running 1/2 pounds of nugs, so I found using a 12" glass tube was best for me. I could see inside to make sure everything got touched and stopped after 3 cans when the butane flow started to clear. I don't think running the extra butane was worth it at 5$ each. When it was close to clearing I would just use my mouth to blow air through to push some of the remaining butane out and call it good. Not ethical but it's open loop tech lol