Look at it this way, if you just finished 6 staring a toon or ship, you are still about a month away from 7* if you only do 8 sims a day. Essentially take the number of shards you have left and divide by 2.667 to get how many days it will take you to 7* the toon or ship. You can then divide the result by the number of times you plan to refresh the node. The math uses the assumption that you will get a 33% drop rate on shards.
For myself, I am farming both, but I know I will have no chance at 7* DR. I'm just spread too thin with too many toons and ships to farm. I am finally down to just XB and IG-2000 in ships but need roughly 100 shards each to 7*. Dark Bastila is at 123, Carth at 205 and Juhani at 222 so I'm at 83 days to finish Juhani at 8 sims a day. If they avoid another faction dump of 4 to 5 characters for the next three months, I can maybe finally catch up once DR returns for the second time.