What's your 'concern' about the Clear Span Engineered Trusses costing $300 each? I mean, Engineered Spans are stronger than 'natural wood' these days. AND, they can span greater distances than natural wood. Are you trying to find Natural Wood Trusses for large spans? (Kinda like fitting a square peg in a round hole ...)
Is there something I'm missing here? IMO, I'd go w/Engineered Trusses ESPECIALLY where natural trusses aren't a 'fit'.