calcium will help with blossom end rot but won't do a whole lot with splitting. Tomatoes are made up of a large percentage of water. When they get 'overwatered' or 'inconsistent watering...dry and then a great deal of water', the tomato itself gets so much water content it simply burst. Picking before ripe and letting ripen inside is about the best "cure" around.
Jeremy, we just got a lot of folks on here who can appreciate a good tomato.
Lord, I do love those things. Every meal goes better with a couple slices of a good fresh tomato!