Actually your bullet should mandate the crimp/amount of crimp.
Some bullets are designed with small, narrow crimp grooves while other have large, deep, angled crimp grooves. What good is a roll crimp if the mouth of the case is not crimped enough to touch the bullet in the deep angled crimp grooves???
Myself I crimp everything like the crimp you used in the 1st post. Using that heavy crimp does 2 things for you:
It equalizes the short start press of your loads. This in turn lowers your es's and sd's which lead to consistency/accuracy.
It takes case neck tension out of play. Everyone talks about longer case life. Myself I rather shoot flies for 15 reloads than hit the paper plate the flies are landing on for 30 reloads.
Those targets pictured above are an excellent example of what happens if you rely on case neck tension rather then a solid crimp when using mixed range brass that's been around too long. WWWWOOOOWWWWW!!!! My cases last forever because I use a lite crimp!!!!
I was playing around with a 686 using 357 cases looking for a plinking load with a h&g #41 110gr wc bullet. The h&g 41 & 50 wc's have a small shallow crimp groove and rely on neck tension to hold the bullet in place while the short start pressure builds so the powder gets an even/consistent burn. The H&G 41 (left) & H&G #50 (2nd from left).
Those targets pictured above show large groups with fliers. They are actually 3/4 shots in a group with 2/3 fliers for the 6-shot group @ 50ft.
The 357 brass I was using was the junk I throw into a box and use it for 25ft bowling pins. It looked like the puppy played with it for a week or 2. BUT my brass lasts forever!!! Can't hit nothing with it but dirt clods or bowling pins @ 10 paces, but I'm saving $$$ on brass.
Let your target tell you what works and what doesn't. Chronographs are always a good thing and will pick up on if changes in crimp will affect the consistency of your reloads. The other thing to keep in mind is powders like bullseye, hp-38, zip are a lot less picky about things like crimp & neck tension. Get into powders like universal, unique, hs-6 things get interesting.
This is why I use a heavy crimp on every 38spl/357/44spl/44mag that I reload. Could care less about how long brass lasts, I want to hit shotgun shells @ 50ft, golf balls @ 25yds, tennis balls @ 50yds & clay pigeons on the berm @ 100yds.