Been experimenting with fluro lamps....

SO how bad is it for the ballast/lamp if i hook up  the red wires on one end of the lamp and the blue on the other and completely skip over the yellow? will it kill the ballast? or the lamp? ... I noticed the ALTO i used was considerably brighter on this setup than it is on the single lamp fixture i have....

Most ballasts tend, some to higher extent (magnetic) and some not as much (electronic), to increase the lamp current when the output voltage is low. When you connected one lamp between Red and Blue, and it started at all (which means the ballast is of the series design), the voltage on the ballast output is half of the voltage it is supposed to work at. This ballast increased the current significantly, which means that it is overloaded

the ballast will most likely overheat and either fail or trip its thermal protection.