We have a few experts here with the massage questions. I've found, even the most legit places that totally don't look like the offer a "happy ending" quite often do, somehow. I think if you want Top or Bottom, Skinny or Muscles: you need to find a place that allows you to select the guy first. Don't rely on someone else to tell you whether they are Top or Bottom, Smoke or Not, as most often they'll only tell you what you want to hear...or what makes you make a selection and go away.
I've also had much more luck with massages in Pattaya...than Bangkok.
Surfcrest