Depends on what part of the country you're in, what kind of weather you have in your area.
Also depends on where your brooder is......in the house, in the garage, in the barn. Also want to consider how many bitties you are hatching and brooding.
I live in Texas (northern/central) and use regular 60/75/100 watt bulbs. Knew a lady who nearly burned down her barn with one of the heat lamps.
You want to watch your bitties.......if they are always crowded up under the heat/light, they're cold......you could increase wattage (say from 75 to 100 watt) or you could lower the light to be closer (as long as it's not TOO close to the bedding). Be sure there are no drafts blowing on your brooder.......plywood, cardboard can help with deterring drafts.
If your bitties move about the brooder with ease, then they are happy. They need to have room to move away from the heat if they want, and go to the heat when they feel chilled. They will self regulate if given enough room.
Best of luck, and watch, your bitties will tell you what they need.