As I said, I've found the 18 to work with a pretty wide range of tuning. There really aren't any hard and fast numbers. For diamond wire tension, the traditional method for measuring tension was to place marks at 12, 24, & 36 inches up from the diamond wire bolt. The tension is determined by where the wires touch the mast with moderate inward pressure. So between the 12 to 24 inch marks would be tight to moderate tension. I don't recall seeing anyone with loose/floppy diamond wires in recent years. Everyone has them at least snug, even the ligt guys.

For mast rake, again I don't know numbers as I haven't measured a boat in many years. I have non-low profile mainsheet blocks (i.e. the bottom block is a triple on top of the ratchet) and in a strong breeze there is about 2 to 3 inches between the lower mainsheet block and the block on the boom. That's more or less how I measure my rake. It's about as far back as possible without the possibility of going two-blocked. After that, its a matter of having the helm dialed in to a slight weather helm and once I achieve that, I don't want to screw with any adjustments.

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