Thank you Starling1, I agree that squares are stronger shapes than rectangles. Nonetheless, I'm 'gonna' go with DangerMouse01's approach, I'm gonna keep it simple and go with the rectangle shape because it's just simpler/easier to build.
The crown will consist of 6 pieces of the same length. I've decided to go with a 3' length per piece after all. The 'wood-crown' will be built as follows: two of the wood pieces will be set opposed one another. Between them, will be two pieces set perpendicularly at the ends, and all four corners will be held together by 2 screws per corner. This completes the rectangle part of the 'wood-crown.'
Finally, the last two pieces of wood that will fall into 2 indentations at the top of the round peg pole, will also, of course, be screwed to and thus hold the wood-rectangle in place. And, voila, there you have it.
I hope everything turns out all right. All the material has been purchased and the construction/set-up will take place and be completed tomorrow.
My main worry now is to make sure that the crown is balanced. That is, that it does not tilt to one side or another.
Thank you guys for all the support and encouragement. Hopefully I'll report back tomorrow with the good news of a good installation outcome.