I'm replacing the front and rear sight on my P10. I bought XS Big Dot 24/7 Express front and rear sight. I took it to a local gunsmith and he said they were a little too big to fit in the dove tail. XS said they were the correct sights they just needed to be fitted. does anyone have experience with aftermarket sights. The local gunsmith didn't want to do any kind of milling on the sights or the slide, in fear of destoying one or the other. I'd like to get some opinions please!