The piezo you suggest will detect acceleration or dynamic deformation (warping) of the piezo's brass disc (in this example that is), but there's no way you can analyze an elastic deformation of another construction component in a quantitatively accurate manner.
The strain gauge approach is much more accurate and reproducable since the strain gauge is inherently calibrated and adds much less weight / inertia to the test setup. Moreover, accurately bonding the strain gauge to the exterior of the chamber is way less troublesome.
The piezo may do as a trigger element for pulsing the strain gauge's bridge excitation voltage if that's necessary, but I'ld not recommend it as the measurement transducer itself.