Hate to start by asking a question, but if successful I'll follow up with a review.
While checking reviews, I found plenty of providers that seemed in for a bit of anal. E.g. on AW alone I found Veronica_a, PETITE_ANGEL XX and Phoenix Linda, and Lacreta on Diva. But I like to take my time, be gentle, not fast&furious style. I don't want to be told after 10 minutes to hurry up and finish.
Age, dress size and rate, the lower the better, but that's all secondary. Independent or agency are both OK, nationality doesn't matter.
Recent questions that were somewhat helpful: "Looking for petite girls who deepthroat/anal" (but I don't care about length) and "Slim attractive all 3 holes hot list" (Not sure if the Veronica mentioned there is AW's Veronica_a).