Success!! Today I stopped at Menard's on my way home from work and bought a clear 150w bulb and redid the DBT. The bulb dimmed just like I was hoping it would! When the sound of FM stereo static (no antenna yet) came up on the speakers, it was in both of them this time. It must be the size of the bulb that prevented sound from emanating from the right speaker. In other words, too much resistance. Oh and BTW, my dim bulb tester works fine. I've used it before on old radios. I even installed a light switch to shut the power off quickly. The next step is to bring up the 400 on the variac and do some voltage checks.
