Yara said..
There is a Walker H28 ketch on Boatsonline in Townsville that has been "converted" to a sloop. Looks like what they did was rake the mast aft to compensate. Could work Ok if the sails are re-cut to suit, or maybe just tacked up to the new shape, so that they can be retored if the owner decides to re-fit the mizzen.

I beat my own drum Yarra its sail,balance for me. I would not fit the mizzen as its no safe for one thing there's a 20 mm between the mizzen bulkhead the the cockpit floor and I need shade and solar before a mizzen the added cockpit area for me is a great bonus the mizzen is about the same size as a sabot sail area . Nothing finished till its finished Yarra
for me it's one thing at a time the mast up the main up and working plus the genoa and staysail comes a lot sooner than worrying about the back end
As long as it's floating around mid january with the mast I'll be happy