Well, aren't you a funny old elf?

It's rare to find people who still use classic astrology. I suppose only those with a closer grasp on tradition would do so. I am a mere peasant and follow the trends of my time... in this case anyways.

Eris is larger but further out than Pluto. If Pluto is included in Astrological charts then most certainly Eris should be. Though I don't know of any software that includes her and I'm too young to know how to figure it out by hand.