Yes I have a lot of seed packets too! and pigeon hole them by month of sowing, which is great for being prompted to sow what is in season, but not always so brilliant when looking for certain seeds! Carrots and beetroot for example, which can be sown over a long period. Salads I keep separately.
Yes well spotted, I planted two per station last autumn of many salads, especially the fast growers and those with large leaves, to have a greater number of smaller leaves. Also I do three or four sometimes: but commercially, where speed of picking is important, I find that two works well, mostly for rockets, spinach, many herbs and orientals. Always one for lettuce, endive, chicory.