I didn't weigh the initial material (trim). The tube is 3 by 24 inch. Sometimes 16 cans was sufficient, and one time 24 cans was needed. It was usually at 17. I looked at it as a cost benefit basis. The initial can will extract a huge amount and will need several cans just to get butane to flow out the other end. The quantity of extract will become less with each can until the point at which it doesn't make sense to continue using cans.
The grower wants a 10 lb active system with chillers instead of dry ice.
RE: Crude Method for Cannabis Extraction