Having a different pre-defined value for allocation vs deallocation scribble is nice because you can then tell if the error happened pre-initialization or post-

Having a different pre-defined value for allocation vs deallocation scribble is nice because you can then tell if the error happened pre-initialization or post-free. $AA and $55 also weren't chosen by accident one assumes, $AA is 1010_1010 and $55 is 0101_0101. Consistent values help with reproduction. The Linux setup where you can choose your own scribbles seems to meet your needs no?