Lena is awsome. Have received from her in Germany multiple times before.
I even learned how to cook it myself thanks to her.
Also has a MTF DIY group where you can search info and discussion on HRT stuff (u'll need to ask her for how to get in):
https://groups.io/g/MTFHRT
Inexpensive DIY MtF HRT.
lena.kiev.ua
The most standard dosage is 20 mg Estradiol Valerate injected every 2 weeks.
Every body is different of course - but it won't have the absorption issues many other methods (especially pills) do, so it generally works out better.
In my case, I'd been using this dosage since May 2018, and have not needed any antiandrogen alongside it.
I've been on HRT since 2016.
Tried pills (6mg/day), gel, patches, for me specifically they did not work. Again, your mileage may vary. Blood tests help get a proper sense.
If you choose injectable, the proper timing for blood test is right before the next shot.
One thing to beware though is, you might get locked out of the German official system if they test your hormones before official prescription and find abnormalities.
Don't admit to self-medicating to any "medical professionals".
Perhaps you can find a way to mess with such a test by adjusting your hormones in advance, idk.
In my experience, their system sucks anyway so...
The most reasonable endocrinologist I found was this one: (Dr. Lars Happel)
https://www.ivf-saar.de/
They send me Progesterone scripts from far away if I confirm my insurance with them, and have been flexible as far as blood testing goes (at some point, once a year at best is enough, really)
Hope this is helpful. Best of luck to you