NZB Play extraction-method

[eternal]

When I use 7zip or stream-unrar to unrar the first downloaded files instead of NZB Play, it creates a file which size is growing.
NZB Play on the other hand already creates a file with its final size.
But for playing MKV's in MPC-HC (i.e. with DXVA) it's necessary the mkv appears in its actual size:
https://www.altbinz.net/forum/index.php?topic=3582.0

Is it possible to change the method of extracting rars, so NZB Play would do it like 7zip or stream-unrar?

Thanks