I have personally had the most luck with OkCupid. Just be very clear in your profile about who you are and what you're looking for. I also had a rule about not messaging people first because of how I identify, but that was mostly because I didn't want to deal with constant rejection.
Tinder worked well for conversation, but I was never comfortable enough to meet anyone.
I have never used it, but a lot of the guys in the Facebook groups I'm a part of have had a great deal of success on Fetlife, which is a kink-oriented social network/dating site. I plan on checking it out at some point just to see how valid their statements are, but not sure I'll stick around since that stuff isn't necessarily what I'm looking for in a relationship.