I think the full length mast are usually only on the DS1. The DS2's have the flotation tank flooring inside the cuddy cabin. My DS2 has a compression post below the cuddy cabin floor to the keel. On top of that is the lower mast section with the lower half of the tabernacle hinge plate.
If the mast was cut a little short after a dismasting, you could get a mast section to make a new lower section that is a little longer than the original section that is between the cuddy floor and extends just above the cuddy top. That would allow keeping the stay tangs where they are on the mast and be able to standard length stays.
I'm dealing with a similar situation on a Rhodes 19 that I'm restoring. I aquired a hinged mast (same setup as a DS hinged mast) for the boat. I have to make the section that goes from the base of the mast to the "king plank" where the Rhodes 19 mast tabernacle is normally mounted for a full length mast. I will have to adjust the lower section until I get the stays to fit right.
John