I have taken so many tips from this site, so I thought it was finally time to give something back.
Since February 2012 I have been documenting my progress as I built my 18'' dome with insulated foundation, subterranean heating/cooling system, and a 450 gallon thermal mass pond. My blog can be viewed at geogrow.blogspot.com!
I overcame the hub issue with some creative cutting of 2x4 struts and plywood polygons. I hope you like it!geogrow.blogspot.com