Q: Can I play Winds of Cloudsea and have X be more than 3 with Raging Shardbeast on my field?
A: Yes. Raging Shardbeast checks the cost of the card. Since Winds of Cloudsea’s cost is X, it’s cost to play may be higher than 3, but it’s cost will be treated as 0 in the hand. (See Shardlight Cost 3.4.2)