I usually use about 4" overlap to connect the limbs to the handle. If the overall length of the bow is 56" minus 7" would be 49". divide that by 2 would be 24.5" for each limb at absolute minimum. Better to add an inch or two to that length for cleaning up each end of the limbs. Also if that length is nock to nock add another .75" for the tips.
Does that sound about right?