...

use Sort::Key::Radix;
my $skr = sub
    {
        my @sortedKeys = Sort::Key::Radix::nkeysort { $hash{$_}{Size} } keys %hash
    };

use Sort::Key;
my $sk = sub
    {
        my @sortedKeys = Sort::Key::nkeysort { $hash{$_}{Size} } keys %hash
    };



cmpthese(
   -5,
   {
       ClassicGRT => $rcClassicGRT,
       ClassicST  => $rcClassicST,
       Jethro     => $rcJethro,
       Simple     => $rcSimple,
       SK         => $sk,
       SKR        => $skr
   } );