You are very mistaken. In your "perfect world" everyone just has a mother plant, and has no need to ever grow any other strain. I'm sorry, but I don't just plan on stressing plants, I plan on breeding them as well. Meaning for the next 10-30 years, I'm not going to have much of the same IDENTICAL plants EVER.
Testing and breeding are totally different things. You're trying to test things, or at least you claim to be. You have a major flaw in your methodology. You will never know if any positive results (should they miraculously occur) are due to differing genetics, environmental factors, outliers, etc. In other words, your tests will prove nothing. You're throwing crap against the wall, hoping something sticks, and calling it a test. Any conclusion will be tenuous at best.
Now you're saying that you are stressing these plants while attempting to breed them. Count me more confused about what you are doing than when you started. If you want to successfully breed plants, you will probably need to take clones. Grow them, take a clone before flower, and keep the clones of the best plants. Breed that clone with another plant that you like the traits of. Rinse, repeat, until you get what you want. Otherwise, like with your "tests," your breeding program will amount to throwing shit against the wall and hoping something sticks. Lol, Good luck with that.