Would there be any disadvantage to doing this with mother plants?????

I have 3 mothers under a 250w hps right now theyre all about a month old but growing pretty slow... Would there be any disadvantage to putting my 1000 watter over them till they get bigger then putting them back under the 250watt?

The only worries you have are too much light (like the light to close to plants) and too much heat (+90*F) if you can regulate those more light is almost always better, and you will see a huge difference between the 250 and the 1000. The most important thing I have found in my garden is getting the temperature and humidity regulated to a point almost no differences throughout the day. (for my strain 419, it's at 78* and 55% Hum, all the light cycle, and no less then 70* in dark cycle)

Good luck, and let us see some data on how much your growth skyrockets