I recommend the MK V for your purposes, based on what you've posted. MK IV's (blue) and MK VI's (stainless) were the polished versions of the same gun. Their rear sights were adjustable (if you could call it that) but were not as rugged or practical. The MK V was the most popular stainless model, and should be available at normal used prices. If you run into an MC1, that could be good for your purposes too, as it was never "spiffed up" cosmetically, but was the same gun inside. ...Deeton