Solid Signal has mis-stated the beamwidth of both their Yagi and their 8-bay antennas as being 60°. Their beamwidth is actually about half of that, depending on frequency.
Specifications for the Yagi from the Chinese manufacturer's website:
http://www.qiaohua.com/products/av-91xu.htm
The manufacturer does not provide technical specifications for the 8-bay model that SS sells, but they do for the 4-bay version:
http://www.qiaohua.com/products/AV-0948.htm Experienced antenna folks understand that when two identical antennas are side-by-side at the correct distance and with the correct combining technique, beam width will be approximately halved in the plane of the stacking. Therefore, a simplified beamwidth would be in the neighborhood of 30° with variation by frequency readily apparent.