I have a T2i with a DIY viewfinder on a thin piece of metal attached to the mounting screw under the camera and my tripod plate under that. I want to buy a battery grip but want to keep my viewfinder set up as well. Would one of you with a battery grip try to mount the grip with a penny sandwiched between the camera and grip? Also with a quarter? I want to know if it mounts secure and if the battery contacts still meet properly. Thank in advance for your testing!