Just got my MN CV1 and 2 this weekend with DB BW crew and a little tip for you. Don't bomb 900 SD (3-4 gold ships), only bomb them when they are in orange or after they've taken a big hit. That means that there SD dropped below 900 and can easily be sunken.
For full 900 SD ships you simply do not enough damage with tier 1 DBs (7 dbs) to hurt ships like those, so it would be a waste of your bombs. You better bomb the AA ships around them or other smaller ships. Those are also more fun to bomb.