Hello, Franklin. I was sailing Edel 540 some time ago. Good boat for a beginner. According to my (unreliable) records, mast height was 7.5 meters with the fractional rig of 7/8. Roughly, the forestay was tied to the mast 1 meter below the top. The rig had simple round aluminum spreaders (slightly bent afterward), and there were two pairs of shrouds, one pair from the top of the mast through the spreader ends, and the second pair from the middle of the mast, right below the spreaders. I can not recall the diameter of the mast, but it was an aluminum, oval profile, possibly somewhere around 25 cm. There also was a backstay, going from the top of the mast to the transom. I was using a 10 mm rope for it with the pulley system for adjustments. As for as the mast was deck-stepped, the rig always had some freedom, i.e. never was too tense.
Hopefully, this info will help you. Also, I can try to reach locally for a person who is still sailing this boat in case you would require more precise info.