The Grip Size on the N-frames is bigger than the K-L frame grip size. However, the real difference that you, the shooter will feel is the "trigger reach" which is somewhat longer. Not a lot, but a bit. If you install the N-frame round-butt grip that has the same configuration as the grip you pictured it will not be a lot different.
You may actually grow to like it. I do not have big hands and find the N-frames comfortable and can get my trigger finger around the (thin) trigger just perfectly to shoot excellent double-action. I actually find the round butt of my 627 a little more forgiving than the square butt on my 28/23, but maybe that's just me.