I like this question.
Last year we cut an octagon frame and tapered the principal rafters. I wish i had done more tapering, especially the principal posts.
I did not feel that working with the tapered pieces was more time consuming, the snapline joinery i use most of the time seems to translate easily. We only tapered in width, however and tapering both width and hieght would mean some stacking challenges...

Our engineer had no trouble working with the tapered timber...