RE: 27MHZ Antennae Legnth
I'm not familiar with that specific receiver but; most receivers are set up to use approximately a 1 meter length (39 to 41 inches) so that may be a good goal to start with. Just do a range check after soldering on the new antenna. Gauge is not real important, anything about 22 to 20 gauge stranded copper wire will work okay and be resonably strong and flexable. Of course you can go to larger or smaller gauge and still be electrically okay.