I think pulse start is for certain bulbs, probe start for others. So, figure out which bulb you want to use, then decide on the start. Don't quote me on this, but basically I think it's some of the high kelvin bulbs that need the pulse start.

Or, if you really want to learn everything about lighting, take the MACO class which is about to start. Probably the $35 you'll spend on the course could save you a lot of money in lighting purchase; (or it could cause you to spend more money on higher quality lighting)