Hi Sam,
Been following your progress, good on ya.
The probs I found with fuses...
(1) not all line has same break strength - might be stronger than hoped
(2) weathering reduces the breakpoint - early releases
(3) often have to replace fuse - especially if it's going to be able save the rudder
Number three is the problem for singlehanders, as a well placed fuse is often over the transom

and in bad conditions
I'm trying a new solution - auto-release cleats that are now available on the market again after a long absence.
http://www.duckworksbbs.com/hardware/cleats/sd002570/index.htmThis link is for info - it shows well how the cleats are designed and installed -- but if I remember, the price I paid was much, much less.
I have two for installation this year --they seem well made _and_ easily adjustable!
Hope that helps,