Hi, welcome to BYC!
250 is the industry standard, but they raise hundreds of birds in outdoor sheds. That is often too warm for home use to be quite honest.
So YES, try your 150 watt light. If you are raising them indoors it should be plenty warm. If they stand directly under the light and peep loudly then they are too cold and you can try to lower the lamp a little. If they sprawl out away from the light they are too warm. But allow for temp fluctuations.
I use 150 watt bulbs all the time, and my house is about 60 degrees. So you may need to adjust according to your temperature. But it should be fine. The whole brooder doesn't need to be heated, just the part where they warm up and sleep.