I just got a manners t5a after much debate. i'm left handed and these were made for right hand shooters. I am going to take a file and smooth out the ridge on the left side of the grip that a right handed shooters thumb rests on. my question is what can I use to add a little to that side to fill in the contours? will the old bondo grip trick work here or is there something else out there that will work better?