The potency of the estrogen is not relevant. The BALANCE between estrogenic effects and androgenic effects IS what is important. You can have a "normal" estrone or estradiol level, and without androgens end up with free implants. This is not uncommon or rare. You conveniently glossed over the fact that people who naturally have zero testosterone end up feminized.
Thats why you can have a massive amount of free estrogen by using aromatising gear with no AI, but if you throw in a hefty dose of masteron and proviron, you will likely be fine and suffer no estrogenic effects, but obviously the more logical and cost effective solution is to use an AI.
Also, relying on east german doping studies is not the most reliable thing to do. The east german dopers largely used dosages of around 10mg for males and females. Its hardly a fair or intelligent comparison when the average joe is going to be slamming 50-80mg at least.
The only way to be sure, is to submit the gear for analysis. Everything else is intellectual masturbation.