I saw a few posts you did today around the forum. Been wanting to tell you how absolutely gorgeous he is!
My guess is DT, possibly SDT once his tail grows back out. When it's finished growing out, too, you can tell if there's some rose petals back there. ;)
It's easiest to tell if he's flaring. (A good ay to get him to flare is holding a mirror.) My marble HM Jade looked more like a DT until he got a bit older. He's almost a year old now I think, and he's a hugely finned HM with rose fringe. A very-not-recent picture of him is to the left, as my avatar. I need to get pictures of how he is now... always changing colors. He's so different from when I first got him.
Speaking of colors, I agree with earthworm88. I think people would label him as lavender, though me being complicated, I'd say he's a lavender with a white belly and cellophane-faded fins.
How long have you had him again?