I have had the tri-band Gem Quad at 60 feet for over 25 years (before the WARC bands) with all loops tied together through a 1:1 balun fed with RG-213. I did replace the original supplied balun with another a few years ago. It has earned a 5BDXCC and Honor Roll mixed and CW in that time. There is no interaction that I can see. A friend who also had one tried feeding the loops with individual coax with no discernible difference in performance. Keep it simple, go through the 1:1 balun with a single run of coax and enjoy. One note on quads in general, it doesn't matter how you feed them, how you tune them or what height you have them at, they all work quite well.