I have the 5 bag 5 gallon set. I used them this fall for my outdoor leaves. They worked good, but I think if I had to chose again, I would buy the 8 bag. With the five bag, the 1st bag separates the leafs(pretty much garbage), the 2nd bag is pretty unpure hash which wasn't that good. The 3rd bag was good, but yielded very little(1g). The 4th bag was very good and yielded the most(4gr). The 5th bag took a really long time for the water to drain, because it is so fine, but was also really good, but again I only got a little(1g). So you pretty much end up with three types of good hash, and in my case mostly one really good hash, and small amounts of two other types of hash. This was after two runs with about 4-6ozs of trim(didn't weigh it).
I don't know how the hash separates with the 8 bag, but with the five bag, when I was done, I was a little disappointed in my variety of hashes. Don't get me wrong, the three I had were excellent, but I just went into the process thinking I was going to have 5 types of hash and ended up with 3.
I think if you just want to make some hash, buy the 5 bag. If you really want to go all out and make the best quality, buy the 8 bag. I have 5 gallon bags and they were plenty big. I don't know if 1 gallon would be big enough, but 5 was more than enough, unless you have a ton of trim.