I've been pocket carrying a 3" M60 J frame fairly often in recent months.
I thought some of my experiences might be helpful.
First, I have a pocket holster from Mika. It's works great when I use it with my Duluth fire-hose pants. These pants have 12 inch deep pockets.
My Mika holster does not work well with a pair of "tactical" pants I tried. The pockets aren't as deep and are cut more vertically so the butt of the gun is clearly visible.
I tried a Nemesis holster that is designed for 2" J frames. The holster is open at the bottom, and the 3" J frame fits well but the barrel sticks out about 1" at the bottom.
It turns out this holster works well with both the Dululth and the tactical pants. The extra inch of gun settles nicely in the rounded bottom pockets. No problems with snags getting the gun out of the Nemesis. The Mika, on the other hand, is closed at the bottom and the gun doesn't go all the way down.
I also have a couple pairs of cargo shorts which work OK with either holster.
I have some other Docker style pants that I had before I got my license, and the pockets are too shallow for carrying the 3" J frame with either holster.
On the grips issue, I have tried a bunch.
I really don't like small boot grips, but they work OK from a concealment viewpoint.
I tried Ahrends banana grips, but they are smooth and tapered and I don't feel like I have a firm grip on the gun.
I tried S&W wood service grips, but they are pretty small.
I also have a Crimson Trace large grip that has places for three fingers, but it tends to print as the butt is quite thick and square-edged.
The best concealment grips I've found are the ones that came on the gun from the factory. See picture below.
They taper down so narrow at the end that they don't print. They accept three fingers and fit my hand well.
And they cover the back strap which has both the obvious advantage of taming recoil, but also the back of the grip is rounded black plastic.
So if someone standing beside me looks down into my pocket, they will see a rounded plastic object that looks much like a smart phone, wallet, or sun-glasses case.
The grips that expose the shiny stainless back strap -- especially wood grips just scream "Gun".