I don't think you can get away from running backstays
to support an inner forestay.
We had a setup like that on our last boat DIVA and it really wasn't much of a problem to deploy...in fact when we were offshore
and expecting it might get rough (which it invariably does if you are near NZ), we would have both running backstays
deployed but a little slack until we decided to roll up the genoa and put out the staysail...then it's just a matter of tightening the runner on the windward side and then tightening the staysail sheet on the leeward side...not so difficult...and if you have to tack...let the sheet loose first then the runner as you go through the tack, then tighten the new runner first and then tighten the sheet.
Its the mast you're trying to protect.
I doubt there's any real way you can do this with permanent stays
We have a similar setup on Elyse which is a ketch
, and it's always tempting to just keep furling
in the genoa...which sort of works except as you say despite foam and rope
luffs it will eventually look like a shopping
BUT the other real issue is that furling
the genoa is moving the centre of effort forward which will produce more weather helm
So when you reef the main, you should seriously consider dousing the genoa and hoisting (or unfurling) the staysail....to keep the centre of effort near the centre of the boat to take load off the helm
Elyse, our new boat being a ketch
is taking some time to learn how to balance all this as we have genoa, staysail, main and mizzen.....but the principles are the same...keep the centre of effort near the centre of the keel
to maintain steerage...
If it gets really bad we put away the mizzen and sail with reefed main and staysail to keep it in the middle.
Has that muddied the waters even more ?