Very nice Joe. I think we may be struggling with a language barrier between Canada and San Antonio Texas :). For instance we don't call supports for rafters, purlins. Here purlins are on top of the roof.

It appears that even collar ties are not the same in San Antonio as they are here in Mid Western Ontario. What we call a collar tie is generally not allowed to be any higher than the top third (mid span is ideal) and it is used as intermediate support for the rafters. Basically it cuts down on the span of the rafter. In order to do that, when they are required they have to be on every rafter and can't be smaller than 2"x4". Enough on the differences in terminology. One thing that is the same in Kitchener Waterloo as it is in San Antonio is the misconception that collar tied keep the walls together. Wrong location for that. Good post. Thanks
Bert de Haan