Sorry I don’t have better suggestions. Tryst and Eros are my go to’s. Part of the problem with Tryst is they intermingled Dommes and Escorts so unless you use a filter you get both in your search results. I suspect most folks looking for escorts don’t bother to filter out BDSM

I use Session Girls occasionally. While it’s primarily for wrestling, I’ve found a few great Dommes there. I also like NiteFlirt and Tryst for finding a Domme. While they are strict on not scheduling via their sites, I find it a good place to find someone, then track her down via her website, email or Twitter to schedule. Though not sure most guys put that much effort in, lol.