my %templates;
$templates{big}{foo} = 'v3A*';
$templates{lil}{foo} = 'n3A*';
$templates{big}{bar} = 'v2A*';
$templates{lil}{bar} = 'n2A*';

sub record_foo {
    my( $end, ... ) = ;
    my @res = unpack $templates{$end}{foo}, ...;
    ...;
}
sub record_bar {
    my( $end, ... ) = ;
    my @res = unpack $templates{$end}{foo}, ...;
    ...;
}

%templates = (
    big => {
        bar => "v2A*",
        foo => "v3A*",
    },
    lil => {
        bar => "n2A*",
        foo => "n3A*",
    },
);




sub record_foo {
    my( $big, ... ) = ;
    my @res = unpack $big? "v3A*" : "n3A*", ...;
    ...;
}
sub record_bar {
    my( $big, ... ) = ;
    my @res = unpack $big? "v2A*" : "n2A*", ...;
    ...;
}