A friend was down at the shop on Thursday and called to say that the J-Tanks were in stock, did I want one? Heck yeah!
I took a mega 510, measured along its length and used a 3-cornered file to cut a couple of slots (this method is not recommended, BTW). I made the mistake of completely filling the carto before installing it and it flooded bigtime after pressing the top cap on... made me a little skeptical that it was going to work correctly, because I thought I'd made the slots too big. It was actually caused by extra liquid being forced into the carto when the cap was pressed in.
Once the excess liquid was cleared out, it was big clouds from non-stop
vaping! No leaks, no dry hits... works great! All day
vaping from one fill.
I do have one suggestion: the inside edge of the tube is square and has a sharp corner. It needs a chamfer to help squeeze down the O-ring when inserting the end cap. I used an X-Acto knife on mine to cut a shallow 1/16" wide chamfer.