Hi Baddox,
What size and year is the vessel you own. From your description it sounds like the D2 is swagged to the caps at what would be top of the V1. This arrangement means that the D2 cannot be adjust independently of the cap shroud. This arrangement makes it impossible to straighten the mast as the D2s cannot be adjusted. in some vessels the D2 is taken all the way to deck level and can be adjusted there (great for riggers as you don't need to climb the mast to adjust the D2s). It is likely that the original set up was a cost saving exercise.
Would recommend that you change to the discontinuous set up as recommended by Selden. You will also need to get turnbuckles for the D2s per the attached photo.