Anyone using the XS Big Dot tritium sights? I'm thinking of one on a CZ as a carry gun... I'd want to keep the factory rear sight but am a big believer on concentrating on that front sight. I've used Mepros and Trijicons but never the XS... Are they that much bigger? Keep in mind, this will not be a range gun and I don't care what it does to my 25 yard groups.