I have been pleased with the results. I put these scales on my Victorinox Manager, and they fit well. I didn't need any glue or epoxy. They were easy to put on. I didn't use a vice, but I stepped on them on our carpeted floor while wearing shoes to ensure they snapped on completely.
The tweezers are more challenging to get to because the scales are not contoured around the edges. So you need to be able to fit the corner of a nail into the notch and under the tweezer head to pull them out. I also need to push the pen harder to lock it into place in the open and closed positions. These are the only cons, and they are not big enough to make me regret purchasing the scales.
I would buy them again.