measuring c sandwiches

I have a need to measure the coating thickness, outer skin thickness, core thickness, inner layer thickness and o/all thickness in large h/comb panels. I’ve looked into a variety of systems. Usonic seems the best way to do this. Does anyone have a solid way to do this/
Tks guys…my first post

Same guy back again. Ultrasonics do work for surface coating thickness measurements, but that’s about it. The sound wave gets lost in air. And they are spendy.
Next question is does anyone know of a good eddy current meter to just measure o/all thickness. I used one ~20 years ago to measure a very large double core radome window panel but can’t seem to find what I’m looking for (a probe and some alum foil!) with a readout meter.
Any help would be appreciated…tks