When growing as many plants from seed as you are planning to this year you may find that a mix of styles suits you best. Some 72-cell trays for your big Spring planting, some 32-cells with insert pots for your tomatoes and cucumbers and a larger number of 50 cell-trays to keep your succession planting tasks on track.
If you are still not sure which cell tray size is right for you, review this article on Selecting the Right Size Cell Tray
for more information on which crops do best in each size. Before you get planting this year make sure you are giving your plants the best chance for survival by reviewing How to Wash and Care for Seedling Trays
. Remember that plants grown in dirty equipment are far more likely to suffer from damping off.