I have been working on my mechanical beasties for many decades. My first many years with crimping wire terminals was simple.....the standard thin plier with an oval shaped hole that just squeezes the terminal to flatten it into the oval shape. I gave it little thought, until the last ten or so years, esp after my work on restoring an MG. So, ventured out into the more robust crimper pliers that have a prong, nib, tit, or something that forces into the crimp for a better grip. Liked them for some of the larger terminals. So, now, on the plymouth wire harness replacement, I thought more of the problems, esp for the open type terminals and special crimpers. So, got a couple types, and found they would not work well. Crimp down the tangs OK but dont grip. Tried the YouTube bit to little avail, and finally went onto the WireFy website, and they show the types of mandrel dies for different types of terminals. What they DO NOT get into is the operation of crimping. So, back into the shop again to try several size terminals and wires, and different crimpers. What I have figured out, with no instruction found yet, it that I can get the new style crimper to close and round the tangs on the terminals, BUT, I then have to go to a smaller size die to finish the crimp and it will actually tighten up on the wire. I am not sure I have it correct yet, but can reproduce a fairly good crimp with the open tang terminal, but have to use two crimps. I may alter my thinking after another set of dies that are on the way....would think this should work in a single crimp. More later on my hateful experience as things progress. I am still trying to figure whether I want to use the old style crimp on the barrel uninsulated couplers, or crunch with the heavy plier that will dimple the fitting......not sure yet. Sometimes adding the crunch of the heavy dimple will open up the terminal which is bad, then it has to be closed back.....not good. Yes, I am old, but how can something so simple, be so complex.