High filament voltage will definately shorten tube life, and eventually cook them totally.
Resistors work great. I normally put low ohm wire wound resistors in all AC filament supplies. They act as an inrush limiter to help prolong tube life. Also, most filament transformers expect to see 110-115 on the primaries. Especially older ones. City utilities tend to run at 117 to as high as 126v to keep up with current demand. You can also use a variac to set it for perfect 6.3. It won't affect the b+.
Resistors work great. I normally put low ohm wire wound resistors in all AC filament supplies. They act as an inrush limiter to help prolong tube life. Also, most filament transformers expect to see 110-115 on the primaries. Especially older ones. City utilities tend to run at 117 to as high as 126v to keep up with current demand. You can also use a variac to set it for perfect 6.3. It won't affect the b+.