PTB
mod has worked for me. I use 20% vg, and have had no problems with leakage. I too ordered xl attys by acccident. PTB in my opinion tastes better, and no bad tasted when the
juice runs low. Experiment with different techniques when rolling it up. There are great you tube videos that will show a few different techniques.
I have not tried the zfm just yet. I just carry a few PTB carts filled with my favorite flavors with me to work and I carry a couple bottles of my favorite liquid in case I need to top it off. I use a small sharpie to label the end of the rubber cap.