Replying to myself again , but just for fun if we disregard prefix we can fairly easily match 32 bits:

1KbhFQVEUk8wMVtiuBURZAQ1PXnsDUqcag


1EEwcrjaJkWLLZDuZA2Rhob3aVM8NwY5tR



or 40 bits:

1NcE7wksPMcydG7bfsGsGdjf2ckzXSfw1R


1H26EaqCrbdHZk2SvqvZDfPHqYGbYqQsJj


Not going to try for 48 bits on the CPU, but with OpenCL code on a GPU it shouldn't be bad either.