I want to build a cradle with two fiberglass shoes to support the hull while the keel hangs above the ground in order to repair some sounding damage. I'm looking for suggestions as to the best location for the aft shoe.

I'm guessing the forward shoe should probably be under the mast support bulkhead - between the keel and depth sounder. But aft of the keel there isn't much structure inside the hull until the semi-bulkhead under the aft end of the cockpit which is 13' from the forward shoe. I'd like to make the cradle collapsible, like a builders scaffold, and smaller than 13' long. Do you think a fitted shoe say 9' back from the forward bulkhead would provide adequate support for the hull?