No real wrong choice, IMO.
Since you already have a J-frame snubbie & a couple long barrel N-frames I'd lean toward the 2-3/4" M66.
I have the new 66-8 snubbie & think it's very manageable & accurate. Get some cushie grips for extended magnum use if you like.
Then, for your next 357, I'd get a 5" or 6" M686 for serious shooting & full loads. My 5" 686+ is an awesome shooter.
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TALO 686-6+, 5" bbl.
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