Already I find his test concerning. Why 223? Why Lapua? Why 10 times? He took the best brass and tested it.
As far as the #of tests, that should be enough to see start some pattern. If a trend starts to develop it could be extended. I am starting to use a similar approach in my load testing. Start off with smaller samples then refine to get statistical significance by extended testing and refining of the more promising nodes.
why .223 and why Lapua ? probably because .223 is one of the most popular calibers and people who buy cheap brass don't won't be as likely to put a lot of effort into. He had just obtained the AMP and is planning on doing a lot more testing before his next book comes out. He did some Win .308's but invalidated the test because he used the wrong settings on the AMP for that brass. As you know the AMP will use different programs for variances in lot #s of for the same brand and cartridge. That was one of the reasons I really thought I wanted an AMP, if annealing does work the AMP is the machine to test it on. Don't despair on the .243. With most of the other concepts he covers and tests in his books .243's are a common test platform
I will not be spending time and resources testing annealed vs non annealed from here on out. The money I save from powder and bullets can buy me Litz's next book and I will read about his testing.
On bullet convergence in this latest book he performed over 60 tests using various calibers and bullets from .223 to .50 cal. My head is still spinning from reading that chapter and it will require a couple of re reads to grasp. That being said I am sure he will be at least that thorough on annealing tests.