A: You would need to use the 47" Country Ledgestone Post Covers and then fir out the 4" sides to 6". The Slatestone Post Covers only fit "nominal" 4x4 or 6x6 inch posts, meaning they are really only 3 1/2 x 3 1/2 or 5 1/2 x 5 1/2. The Country Ledgestone Post Covers fit "true" 4x4 or 6x6 inch posts.
A: The inside dimensions of he post kits are 5-1/2" x 5-1/2" (Meant for a 6x6 post).
A: Yes, you can stack to reach your desired height.
A: With this 8 x 8 x 41" Post Cover, you would have to screw the Numbers in vertically.
A: This is a "one" piece post cover that slides over a post. One per box. The 2 Piece Post Cover is also 1 post cover but is designed to fit around posts. Also one per box but in 2 Pieces.