Hello, the new Sony A6700 camera uses an E-mount, so this model is compatible. 

Dear customer, Thanks for this question, we already did instruction picture and tips for "how to remove the lens adapter", plz see the instruction picture in the "Product Description".Hope it helps 

No, there are no click stops. Only a hard stop at full open and full close. 

FD-EOS fit for Canon FD mount lens and canon EF mount camera body. canon 60d is EF mount, so the adapter ring can work with your camera, but you need to check your lens mount. could you pls let us know your lens specific model? service(AT)kentfaith(DO NOT)com, Please note: It is not same between Canon FD mount and EF mount, this adapter ring is only for Canon FD mount lens, please contact us if you want to purchase for Canon EF mount lens. 

The adapter clicks on the lens. It has a small dark gray colored lever (not the white plastic tab to change aperture), level to the outer edge of the bottom ring accessible when removed from the camera, grab the whole adapter with your left hand and push the lever in with your thumb, and while pushing, rotate the lens with your right hand to remove it. You need to push in that lever to unlock the lens.