I don’t think this info has been released from PSA, but seeing this new mag is proprietary - it may take aftermarket companies sometime to develop a mag/base plate extension.
This is also 365x/G43x size, so it will be slightly larger for the hand versus a Gx4
Having “bear paws” for hands most compact pistols do not feel good unless I use an extended mag. Yet I do carry a Ruger 380 LCP MAX in my pocket at all times. Better than nothing.