How to choose SDM or RDM Windsurfing Masts?

What's the difference between sdm and rdm masts? 

• The primary difference is RDMs (Reduced Diameter Masts) are narrower in diameter than SDMs (Standard Diameter Masts). RDMs were originally introduced for wave-sailing as a solution for durability in waves due to their extra wall thickness that is more resistant to breaking when exposed to extreme flex in surf conditions.
• The RDM masts are compatible in curve with SDM masts, RDM mast is softer, more forgiving feel and durability, while the SDM mast is for faster response.