WHen you say the brake light switch needs to be adjusted not tightened, what exactly do you mean by that remark? Please elaborate!
The brake light switch has "threads" on it when it fits into the bracket...it can be raised or lowered as needed to be at a proper height over the pedal...IIRC you remove a clip, slide it up or down as required, snap the clip back on.
Bulbs will cause the fast flash if burned out or reversed, like he said, due to incorrect impedance in the circuit...but they also do the same thing when the rear circuit is open as happens when the multiswitch goes bad...you said moving the signal stalk slightly will make them slow down to correct speed? The lights are working back there when when you make that happen, most likely...have someone watch while you do it...