I use the Xaircraft battery mount but have tape on the bottom and then velcor on that. Every lipo has a strip of velcro on the casing so it sticks onto the mount. This stops it from shifting in flight. I then use a velcro wrap strap and secure it tight. I also have velcro on the top of the battery mount so the strap can't slip either.
One of the things you may not be aware of is that the mount is designed to give up on impact. It will drop the lipo to the ground on a heavy landing. This is to help dissipate impact by reducing impact damage to the lipo and the air frame should the worst happen.
I did look at making a Lipo cage to mount to further protect the lipos but never got that far because I use 5000mAh through to 8,400mAh lipos meaning quite a differing size and the ability to shift the weight to balance the machine is made easier just using velcro.