Estrogel is entirely possible to dose topically and not go tranny, yes, as you put it.
Here's the thing, at some point in your youth, you had way more estrogen and far less testosterone than you do now, probably even in your teens. If you get your topical formulation right, yes, you can concentrate the positive effects of the estrogen on your scalp and mitigate the systemic effects of the estrogen through dose titration and using things like betaine hcl to increase (and in my case drastically increase) your liver's ability to metabolize estrogen systemically.
You absolutely can find a balance where you have "enough" testosterone, and enough topically applied estrogen to maintain regrowth. However IMO this is basically like the final boss of hair loss challenges, where finasteride is a roulette wheel, it will either work for you or give you rubberdink and/or possibly worse it can make your head shed more , topically dosed estrogen requires both patience, understanding and skill in creating a formulation that won't do f*** all or give you tits.
It's possible, but probably not by everyone, until a standardized practice has been established.
Maybe I will be one of the first, we'll see.
The OP of the hormone thread where he grew back his hair basically accepted his sides and just kept powering through with more estrogen and androgen antagonists.
I'm of the mind that I really do care about sides. I'm also a perfect candidate for this research because of my naturally high t levels, unlike any other point of time in my life save my early twenties, I can roll out of bed and look near shredded doing nothing, if I were to start working out again, for a couple of months I'd probably be a beast, but I would also probably jack my DHT and test levels even higher and threaten my hair regrowth.
That's the power of testosterone though, it will maintain muscle tone and melt fat off you if it's high enough and estrogen is low enough, so we'll see how I fare when I start applying a low concentration dosage of estrogel in a serum form and see how much my body weight and composition changes.
I know I won't be able to eat half a cake the night before and wake up with a near six pack, but I really want my silky thick hair back, it's "ok" right now, but it's not what I want.