I have an entire array of regular light bulbs for brooding. I hatch both quail and chicken chicks. I have a brooder house for the chicken chicks that they go to after 10 days. My quail babies may end up there this hatch as it is colder than expected this year.
So start with a 125 watt and see what the temp is in your set up. (Brooder light and thermometer should be dedicated just for that brooder setup) If it doesn't get to 95 degree, use a larger wattage. Make the set up so you can raise and lower the light easily. I usually end up raising the light during the day and lowering it at night. About every 5-7 days, I am changing to a lower wattage. So I keep 100,75,60,40,25 wattage just for my brooders. (Brooder house uses 40-25 in winter-summer for the last little bit)
I brood my chicks in the house in rubbermaid tubs for their first 10 days then out they go. I start with 100 watt. But out in a shed you will probably need a higher wattage. You may need the 250 watt, I use one in the winter (February sometimes) for my Brooder House. You just have to try it and see, at different times of the year you will use different wattages. You should also have extra's in case the thing burns out on you when the stores are closed or 10 O'clock at night when you don't want to run to the store, so get 2 of each. Seems to happen all the time.
Brooder temperature is something you end up playing with at each hatch. Gives you an excuse to check on the babies and admire them while they are still cute. And plan out recipes according to their size.
Remember 95 1st week, 90 second, 85 third, 80 degrees until completely feathered during that 4th week.