In order to craft one of every piece of Sunplate/Skyware furniture, you'll need 142 (157) Sunplate Blocks.
Creating large structures out of Sunplate Blocks may require farming Fallen Stars.
Sunplate Blocks, like water and cloud blocks, reduce the chance of Meteorite falling in their vicinity. A meteorite requires more than 600 "solid blocks" in a 900 block (30x30) area to spawn, and Sunplate/Cloud reduce the "solid block" count by 100, so 4 Sunplate/Cloud blocks will prevent meteorite impacts within 30 blocks.