protos in perl6

proto ndr(Any, Int:D $radix where $radix>0=10) {*};

multi ndr(@vals where so all(@vals) >>~~>> Int, Int $radix)  {
    1+floor log (1 max [max] @vals>>.abs), $radix
};

multi ndr(Int:D $val, Int $radix) {
    ndr [$val], $radix
};

say ndr(257,16);

# This works fine.  Now, how do I allow the proto to
# govern subs with any number of positional parameters
# preceding the Int $radix ?