Had mine for 6 months. I have to take a hammer to hit it hard enough to knock off one side of the mount in order to tip the seat to the correct position. Torx T25 is also a very poor choice. DO NOT BUY IF YOU EXPECT TO MAKE SEAT CHANGES ON THE TRAIL. You really really really have to WAY overtighten the ONE bolt if you want to have the seat clamped in firmly. Even so, the seat will with hard but-hits. Yes, the rails are the right size for the seat post.
Looks great, but it must perform!!! Giving it one start for looks. Otherwise a goose egg.