I was amazed how much can go into a wedge fitting to get the grind for your shot shaping and local soil conditions. My local bunkers are nothing like the bunkers at TPI, but they do vary locally based on the amount of local clay has seeped into the sand. It's hard to quantify "open the face some" so getting fit for your common shots around the green at or near you primary course will give you the best answer.

I have a 54-10S (bent to 53) and 58-08M. Both will work in a bunker. The S grind is easier in hard sand and tighter lies. M grind is better out of thick grass.

The bounce on the 08M grind is a bit deceiving. Do an eye ball of both and one will see more bounce on the leading edge of M grind.

I played with an SM4 54-11M between 2013-2016. Played with SM5 54-10S between 2016-2017. As far as bunkers, I was able to hit either out of soft sand. The S grind is better for pitching, chipping and hard sand (long shots).

My greenside bunker wedges are the 58-08M and the MD3 64/8. I use the former out of wet or soft sand. The 64 is very good for hard sand and very short soft sand shots.

Hey Justin, I have the S grind on my 56 and have hit my buddy’s M Grind 56. I found that the S is good from bunkers if you like to hit down on it, however if you like to keep your swing shallow, the M is better. All in all they are both good grinds from the traps, they do vary depending on attack angle.

Hope this helps!
Jack

I used to have a SM5 56.M used it for bunkers & fluffy lies around the green found it ok.
Had a Vokey fitting tried the 56.M but I found the 54.S performed a lot better from bunkers even without having to open the face. So I went for a 54.S & 58.S, The 54.S is great from bunkers, fluffy lies & chipping.
The 58.S is good for bunkers & fluffy lies. I'm very happy with them.

I just got an SM7 56-08M and it does EVERYTHING. I did a soft sand bunker, chip and pitch off tight lies and I love it! My setup now is SM6 50-08 (bent to 48), SM7 56-08M and MD3 64/8.

This is an great topic and advice for the golfer that just goes into an store an asks for an 60 in relation they have know idea what there getting.
Having an Vokey fitting is key to knowing what grind bounce lie your getting.
I had an 60 s grind 2 degree flat 10 bounce
Also my 56 s grind standard lie 8 bounce
And since my fitting I can tell the major difference
It’s worth getting an full fitting so that it fits your swing plain.