A good question! A 10 to 12 inch crappie should have several more years left to spawn whereas a 16 to 17 inch sow may be nearing the end of its productive life. Those 12" do eat better for sure! I think that this time of year you should just take enough to have a good, fresh fish fry. Stock the freezer with limits after the spawn is over, not when it is easy to limit. You might have to go more often , but Limiting out is not that important...... is it?