Another option for determining when to water is a moisture meeter. Moisture meters have received a lot of bad press, and justifiably so. Relying on just a moisture meeter alone is a bad idea; it should be used in conjunction with other methods such as weighing the growing container before/after watering. Once I've determined it's time to water, I force myself to wait another day or two. However, if the plant starts wilting for lack of water, I know I've waited too long. Overwatering often shows in the form of yellowing leaf tips.
On another note, looks like Barney's has some good genetics based on the appearance of your baby girl. I've been getting my seeds elsewhere, and the ladies have shown some inconsistency. My grow before last resulted in buds that looked very much like White Widow which was not what they were supposed to be, although it was great smoke. My last grow, four girls, looked very different from each other, more so than you might expect from simply different genotypes. Temp, humidity, soil, nutes and lighting was all the same.