My first tries sucked in return but this time around I got about 20% my self. I did use better trim but got a smaller in circumference tube and used 2 coffee filters instead of 1. I'm not sure what made the diff. the smaller tube or extra coffee filter but am happy.
I've switched between using one or two or five coffee filters, and honestly don't see a difference in yield until I hit five, and it was very small.
Good trim from good bud makes a difference. My friend had some stuff that smoked great, he blew actual buds, and only got 10%, and using the exact same methods I use to get 20-25%+.
The biggest thing that I think made a difference for you is the smaller tube. Moving to a smaller diameter will defiantly increase it. You can get it too small but they say smaller is better then the can sized ones. I think mine is barely an inch, maybe an 1 1/4" in diameter. I only use one coffee filter, pack it pretty tight. You just don't want pockets where butane can just run through quicker. Like when you first water a plant with dry soil, and it drains out the bottom fast. You don't want that.
