what is the correct rake on the mast? (I suspect that my mast is too far forward because in low winds there is no windward helm and the rudder feels very strange with no feed back when you move the tiller)
what is the correct tension in the shrouds? (the previous owner advised me not to fiddle with the turnbuckles but I am going to have to replace the toggles so I will need to re-set the shroud tension)
what is the correct pre-bend in the mast?
As suggested I got onto Warren Fraser at Associated Rigging and got this response within an hour. I must say I have never had such a quick and helpful response to a technical query. Can I suggest that you put Warren's notes on setting up the mast into the web page? I have asked him if he minds and he said that not at all, the more knowledgeable his client base the easier his job will be.
600mm sounds too much as far as rake goes and I am sure you are replacing the bottom bits of the bottlescrews because they bent whilst stepping and unstepping.
My forestay spec is 8 565mm length overall. First check that yours is the same. If not then adjust it! (the entire set up revolves around this)
Then load the cap shrouds against the forestay and balance the bottlescrews to ensure that the mast hounds (where the stays attach to the mast) are exactly in line and over the mast heel (and in turn the keel).
Then set up or rather tune the lower shrouds to get the mast straight. This can be done by sight by looking up the mainsail track and turning the respective bottlescrew to straighten the middle panel.
We really load the cap shrouds on these little boats and I mean LOAD so that they are guitar string tight. This forces the middle panel of the mast to pop forward and bend the mast creating the correct mast bend and in turn the correct forestay load. Under stiff sailing conditions you want around 50mm of forestay sag and no cap shroud sag.
After the cap shrouds are loaded then tune the lower shrouds accordingly. Be careful as a few turns can make a huge difference. I would aim to pull the mast back at the spreaders leaving around 90mm of bend at the cross trees. (Use the main halyard by attaching it to the mainsail tack pin and pulling up tight)
There is no absolute load figures for the H-23 but what you must avoid (and this goes for all fractional rigged yachts) is for the cap shrouds to become slack when the adjustable backstay is pulled tight up.
It is great you hear from you and I hope to help you in anyway possible, please feel free to ask anything. What may seem to be silly questions often prevent costly mistakes. If anything is unclear please ask.