Yeah that's a bit of an issue when painting clear coat over a base that's typically flexible (plastic)
His chroming process is quite magical (and expensive). Many cheap manufacturers of hydro-chroming products have issues with the chrome yellowing overtime, evidently, Justin has mentioned that he found a supplier which did not have this issue.
If the corners are flaking off from where it was cut, I suggest doing a clear coat over them to prevent them from flaking further.
My field of painting only goes as far as industrial work though (One colour, one engine), Daniel has far more experience when it comes down to the small nuisances though as seen in his amazing skills on the needler, ray gun and halo 4 helmets.