Found the answer to be more guns aka more ships and to have max. belt armor, so go with more funds as neither enh. guns/torps or survivability will do much for DDs
Build them small and with as much balance to them as possible, to help keep pitch and roll low and you should be able to get 6-7 DDs.
The design I got them with was, 800t displacement, 25kn, very short range, standard bulkheads, 3-exp steam, Harvey armor, reinf. bulkheads, Anti-flood I, heavy shells, reduced torpedo ammo, guncotton, adv. hydraulics with a 1.5" Belt and turret armor. 4x4" guns (1 front 3 rear) 2 enh. funnels with a single tube torpedo in between them. 0% offset, pitch 9 roll 0.8
Upon start of mission, pause check weather restart mission if few or no bonuses, maybe split DDs in to two groups, select HE and set guns to aggressive, torps to off, speed to 19kn, keep BB alone with all set to aggressive plus HE. Target TBs as soon as it possible, help BB to stay on them too. Switch torpedos back on when you cripple one and it stopped moving.