Rugged Case for a project

Looking for a rugged case for a project. I want to mount my S6 on my roadbike (similar to quadlock) except I already have a Garmin 1/4 turn mounting system. I have a 3D printed ABS piece for the male portion of the Garmin mount and I'm going to adhere it to a Galaxy S6 case. I've been looking on Amazon but I'd like to get some first hand experience. Need a case with a hard plastic back that I can scuff a little bit to glue the mount to. Also needs to hold the phone snugly. It's going on a road bike so shouldn't be too rough on it

The garmin mount is about 1.5" circular

Are you using a case that could possibly fit the bill? If so what is it. hard to tell from pictures sometimes