GPS tag modification

Any hardware engineers in here that can provide support with modifying GPS tags for pangolins? I will be deploying GPS tags on white-bellied pangolins and need to modify the point to attachment (i.e. base of the tag). The manufacturers are reluctant to make this change, however, they make good quality tags and given the tag is about 15g, I think replacing the plastic base with a harder material won't significantly increase the weight of the tag. Thanks!