I for one have never been thrilled with the new plastic seatpost mount that comes with otherwise completely AWESOME Dinotte 140 taillight. Too few mounting options and too flimsy for my liking. I decided to look into a suggestion I read on another forum and get a Minoura SwingGrip to mount the taillight on. Without a doubt, this thing is rock solid! It offers quite a bit of up / down flexibility as well as room for my (yet to be re-installed) PB SuperFlash.
If you've been wrangling with finding a decent alternative to the Dinotte mount - this is a solid alternative IMHO