Finally, I think I got it right. I became concerned about "snow-load", so I decided to add two additional long secondary ridge poles to the top for stability. Fortunately the extra .5" tees (H) and crosses (I) parts were available locally!
Here is the final design. Enlarge the pictures (click or double-click), cuz not all shows at normal view.
I am working out the order of construction. I think it best to construct the top first. You want to make sure to get all the cross-pieces square to each other, so constructing it on a flat surface like a garage floor or patio is probably best. If you construct it on a nice flat basement floor, you probably won't be able to get it out... ;)
Since the top (with the cross-braces connecting the arches) is self sturdy, it seems easier to construct the bottom later, as a good top will automatically lead to a solid straight base.
OK, off to work out the order of construction...