I have a couple of suggestions if you suspect bad nano-coat: If you are evaluating SMT stencils, Add a stencil coupon. In that stencil coupon place your typical pads, steps, et cetera. Also add a tape grid. This is an altered grid resembling the G coupon used for soldermask adhesion. Most stencil houses will add this to your stencil layout at no charge. If you are looking at other parts with adhesion issues, then I suggest a Fisherscope ST200 (or just give Fisherscope a call as this may be dated or insufficient to read the coating thickness you are applying).