I have both.

If you want to PM me, I can get measure the thickness of the grip in a day or two unless someone else has them handy right now. I am pretty sure that they are the same. If there is a difference it is not significant.

Yes, the wood grips add a bit of thickness over the stock Hogue factory rubber grips that come with both the MK and the K. My hands are small and slim and I don't find the "extra" thickness to be a problem. I can go either way, but I prefer the classy looks of the wood. I have wood on my MK and the stock rubber on my K.

No, without a longer magazine (7 rd) or a Pearce mag extension (on a 6 rd), your pinky will not wrap around the grip of the MK. With the K, it will. I don't have a problem shooting the 6 rounders, but it does take some getting used to.

You might consider handling both at your local shop if you can find one that has both in stock. I never could decide which one I liked the best....