Battery holder for P47 3Dlab plane

I have a 3dlab P47 and wanted a better battey holder, also I figured I could use it to adjust the CG. Both holders have a lower recess to allow the batteries to be strapped in with a velcro strap. Once secured the holder can be locked in place in various positions. I hope this will give a non moving CG weight. May fit other models, you can just adjust overall size in slicer, or if wrong height/width for you use the flat one.
Two are 'cage' types, one has notches on one side so you could use