So what's the go with this mast / sail chart, is it really very accurate or more a rough guide line when trying to mix and match up combos? I ask as I run a 5.7 Severne Blade on an RDM Ezzy mast, and according to the chart it's the red block of death, but it rigs so sweet and is an absolute joy to use.

Now I'm looking at a used NP 460 SDM mast to run some bigger sails (7 to 8 metre stuff) and according to the chart most brands run average at best. I've spotted some Servene Code Reds that are the right size and price, but they too are red lego blocks