What are your normal iron shafts? The s200 weighs 128 so if you like that in your other wedges the 115 is way to light which is why you're probably having thin issues. You can probably grab a vokeys pull for cheap of eBay.
If you want to switch I would go f grind. I've played both. Probably had better turf interaction with the d but overall the f was just more forgiving. You're never going to manipulate the club enough before just going up a loft. There is a reason 0 pros play the m or d grind in approach wedges.