I have built and flown at least 5 D.B.'s in the past 23 yrs,, and have 6 more kits to go!
there is NO!!!! bad tendencies of spin recovery,, on any of mine when i released sticks on everyone i had there was IMMEDIATE stop of rotation,, this plane tracks and does what you want it to do to a tee!!i never had over rotation of one,, not one in probably after at least 2000 flights!!

im not saying your hasnt,, but if it does there must be a reason for it,, i dont think its in design,, but there are at least 2 other critical factors that affect spin,, CG,, and shape of leading edge,, you may have it too sharp,, im sure theres a thousand people out there that flew D.B.;s they were one of the most populay,, for good reason,, did anyone else have a spin problem??? did you find out why?? id be curious just dont want to find out on one of my next 6 i build!! maybe someone can help us all if there is a hidden flaw in design thanks all,,,RD