Rossi Rifleman

Almost all pistol ammo will need some sort of crimp. The style and amount also depends on a lot of factors. I don't load .357 with jacketed bullets.

Probably the oldest and least scientific technique is to measure OAL of a dummy round. Then with moderate thumb pressure, hold the assembled cartridge horizontally and push the nose of the bullet into the side of your loading bench. Then measure it again and compare the OAL. If you shortened it by more than two thou, you need more crimp.
You've got to remember that in a tubular magazine, spring tension tries to push it in and recoil (especially in a revolver or semi-auto pistol magazine) tries to make it jump out.

I'm running 13.3 grains of H110 under the 180 grain Hornady XTP.
Just made another 200 today.
Excellent round for Texas Pigs.

@dpowers
Maximum COL insures the round will fit in a revolver chamber.
Your range of COL is fine just as is.
Don't go too crazy chasing perfection in that.
The difference is from minor variations in the shape of the bullet and how it meets the seating die.

As for flare, I prefer not to be able to see it.
If you can see the flare it's too much.
Open the case mouth just enough that the bullet will sit on the mouth without wobbling.
I can't actually insert the bullet into the mouth.
But that's me...

The only serious advice I could offer is swap the digital scale for a good beam scale.
Gravity doesn't wander as much as electrons do.

I have a digital scale, but it's for rough estimates only - to 4 decimal places...

OP, let me throw another case prep step into the mix. Slightly chamfer the inside edge of the case mouth after resizing/depriming. Only need to do it once for once fired or brand-new brass. Not really necessary for jacketed bullets, but almost required for lead slugs. Helps keep you from shaving the bullets.

I recently used the 158gr XTPs on my .357. They appear to work well.

I also used Redding profile die for a slight crimp.

I did the same today for my first go at 44-40.

Hornady XTP bullets are my best bullets for meaty targets. I’ve developed individual loads in 45 Colt & 357 mag for my 92s that are “dead nuts on” at 100 paces. That’s about as far as I would “reasonably” push a pistol cartridge.
I’ve used the Lee FCD die, but am curious about the Redding Profile Crimp Die. What does the crimp look like? I’d really like to see it compared to the FCD crimp.

The Redding die does not have a collet in it like the FCD. It has a couple of rings inside the bore, instead. It starts off with a taper, and if adjusted down enough, it produces a very nice roll crimp.

It should be noted that Redding states that it should not be used on rounds that headspace on the case mouth.

However, it works very well to remove the case flare and provide a little more grip on the canellure without resizing the bullet when one does not insist on cranking down to the roll stage.

Reputedly, it does not distort thin wall necks as a FCD has been known to do on the 44-40.

I have several FCDs that I used to use on my various AR calibers. Normally, I don't any more as I don't see any movement in my loads without a crimp.

If I can find a means to reduce the file to 240kb and be "seeable"

I like a little more than that; if I'm going to bother with a crimp*, it will center the crimp groove and you'll be able to see the case mouth crimped into the very bottom of it.

* A.C.E.
Always
Crimp
Everything

Looks like a lot of crimp to me which is okay in .357. But I would not want more in concern of breaking through the jacket. I'd put a little more on cast, the only thing I load for .357.