This is literally the 2nd result from googling "letro dosage for bone growth"
https://pdfs.semanticscholar.org/6aef/31acd8c61c356df0c6d6b697d6db38c246cc.pdfI'll say a magic number and say... take 10 letros a day. Let's see if you can read the research paper all the way to the end, or you just take the easy way out and do what I say.
It's pretty obvious you're young and quite lazy and want the answers fed to you like a child, but I would seriously consider taking these hormone altering drugs and doing some research on the topic before continuing. We are not doctors, this has been said in your numerous threads already.