Hi TsukiCat,
Unfortunately, there are no "clear answers" in the dating world. Everyone is an individual and outcomes are unique.
I have dated some as a post-op transgender, mostly pursuing relationships with women. All I can tell you is I got a few dates, but almost never a second one after they found out I was transgender. There was one exception, and I do see her from time to time, and we have a casual intimacy that is comfortable for both of us. When we have slept together, it is mostly cuddling and caresses.
As far as lesbians dating pre-op transsexuals, I would guess that is a different issue. The cis-lesbians I have conversed with were pretty much turned off by the thought or sight of male genitals, but again, everyone is different. All I can suggest is being honest and up-front about things. As one lady told me, "I am completely supportive of trans women socially, but we get turned on by what turns us on, and I am not sure dating a trans woman would work for me".
You have to respect other people's choices. If the chemistry is not there, it's not there. When it is, it's a blessing. I recently met a pre-op trans lady, and she is terrific. I am very attracted to her, and could definitely see having a relationship with her. I think she feels the same way. So you never know where you will find love!
With kindness,
Terri