Most people use Strong Line to eliminate external bars. How much can be eliminated is a tough question because it depends on the size, design and intended installation of your panel. Remember to error on the side of stronger.
For Lead: The Strong Line is placed in lead channel during assembly. The panel must then be cemented to add strength and prevent the Strong Line from twisting in the channel.
For Copper Foil: Strip is placed between foiled glass pieces before soldering. Once soldered on both sides of the panel the steel strip cannot be seen.
25 foot roll - 0.020 inches thick - 0.114 inches wide.