Some background:
I recently acquired a copy of Epic duels and wanted to go all-out in protecting and organizing it. I had some leftover Ultra Pro One-Touches ( https://www.amazon.com/Ultra-Pro-One-Touch-Horizontal-Resealable/dp/B00J01XP52) from when I was sleeving Kingdom Death location cards , but they were FAR too wide (as seen in the first picture).

So, I heated up my soldering iron to low (20w setting on mine), and after trimming the card to a proper width, put the edge on a wood shim, then placed a metal straight-edge a couple millimeters in from the edge. I then ran the soldering iron point slowly down the edge of the straight-edge a couple times and voila! I had a perfectly-sized sleeve!