Sounds like you're itching to tell us more Derek, & I'd be glad for some professional feedback
For my design, I have the simplicity thing sorted; no hammer beam truss, no octagon pendant tower, not even a hip or a valley. Some folks seem to get away with this in a first time build mind you!
At what level were these mistakes apparent; do you speak of ruptured joints, or misplaced mortises; ie. were they really mistakes which professional consultation would have identified, or were they problems of working practice due to inexperience?