I also used the 250 watt bulb with a reflector this last spring. I actually had to use two of them for the first couple of weeks to keep the temperature at 95 degrees. I recommend setting up the brooder a couple of weeks before getting your chicks. Leave the light(s) on for 24 hours before checking the temperature. It can take a few hours for the brooder to warm up. I was using a steel watering trough in my garage. I will be using a wood brooder this spring and plan to test it out a couple of weeks before getting the chicks. By the way, set it up just like you are going to be placing the chicks in there. The temperature was different after I put a couple of inches of wood chips (covered with paper towels) in the bottom of the brooder. And don't forget to turn on the heat lamps 24 hours before you bring home the chicks.
My first brooder had a 250 watt white light. Those chicks were FLIGHTY! Second brooder I changed out the white one for a red lamp and the chicks did great.
Reptile lamp should be fine. Doesn't matter what the heat source is, gas heating, wood heating, human heating, mom hen heating, as long as they can be at about 95 to start. That said, I use a 100W regular ol light bulb for my chicks on a dimer switch. If they are inside for some reason, a 40W is often just fine for a dozen.
I just found a 125 Watt Brooder Heat Bulb from Sylvania at Lowes yesterday. But they are not clear or red, they look cloudy almost like a grow bulb. I use a Red Heat Bulb at Night and add a (Full Spectrum Florescent) white light during the Day.
If they are inside a 250w bulb is way over kill and you might cook your chicks or burn down your house. Someone melted a thermometer using a 250w bulb on an inside brooder. A 60w bulb usually does fine but if the lamp is higher up or your house is kept very cool a 100w bulb may be needed. Most reptile bulbs I've seen were only 40w which is usually too low unless you keep the house quite warm and have the lamp sitting on a low brooder but I'm sure you can find at least 60w ones which should work. It would be best to use the same fixtures with reflectors as the 250w heat lamp bulbs. Either get one at your feed store or many stores with a hardware section will have them among the shop lights. I got 2 at walmart for less than what 1 costs at the feedstore.
A lot depends on where you're setting up your brooder & the temp in that place. Here in hot 'n' humid South Fla I keep the chicks in a box on the patio and use a desk lamp with a 60 watt bulb. Whatever you use, it's not essential to keep the whole brooder at an even temperature. It's better to have the lamp near one end and let the chicks move in & out of the heat at will. If they stay huddled under the light it's too cold overall, if they crowd the corners in the dark it's too warm, if they bop around the brooder going about their chicky business it's just right.