Using a hardness tester is quite simple. It may require that an A&P needs to witness the test, but using the tester will not be an issue as long as you can pisition the tester on the part (no funky geometry).

The internet is a wealth of information. Maybe try youtube and see what you find on the eddy current testing process. It may not be that hard to determine that testing these parts is not that hard and then you've aquired a valuable skill ad well.