Try our new info resource - "Aladdin's Cave" (Main menu)Just added a separate link to Ash's Dropbox thread (shortcut)
CP means Candle Power, Too fast a flash on an old style can is too high a load but on a modern electronic type can mean a bulb out. Dont forget US front flashers are twin filament
On the two wire filament, only 1 is connected to the indicator circuit. The other is permanently fed with side lights so has no bearing on relay.