Thw GP Waco has an antenna tube built right inside it. MOST, if not all of the antenna will fit in the tube (it's a pretty long plane). If any is left, you can just loop it around the readio compartment. Will you lose range? yes, but it is not nearly as much as some people think.

I have had two separate incidences where antenna wires were not installed properly. One where the antenna was just bunched up in a rat's nest in the radio compartment and one where the antenna was still wrapped around the Rx. In the second instance I got a few nasty glitches which caused me to land early, but in the first, the entire flight was flown successfully. I don't recommend doing either, but it just goes to show you that you can get away with a LOT. just be sure to loop the wire and not fold it over itself.