I am a proud new owner of a ruger mark ii 4" tappered barrel with fixed sights. Has anyone setup this with adj rear sights? brownells shows a few options, where some have comments associated with them that indicate that there was a gap at the bottom of the rear sight and the top of the dovetail. I realize that this may be a bit more involved since the front sight has to be matched to the rear sight. Any helpful hints are greatly appreciated. Thanks in advance.