I use the telrad and an optical finder.... set up on my Dob like so....
The base plate is 175*55mm in size - quite big. It comes with two full length double-sided-tape pieces to stick on with, although you can use the holes and screws if you are particularly brave and trust yourself with a drill and your OTA!
I'm going with the tape, seems to hold nicely.
The tape is on angled pieces to match (not so perfectly) the curvature of the OTA - would probably match a 6" perfectly, 8" quite well.
I just stuck it on then use three zeroing knobs to aim it and you are done....
Hope the pics help.
