Build Flash Umbrella Which 35mm Film Speed Should I Use ?

Which 35mm film speed should i use ? - build flash umbrella

I start up with a portable very small studio. I offer this set comes as more money, but now ... I use: 1 umbrella, white bulb 30Watt cold flo, which is equal to 100 watt reg. Light bulb power. It is also used to fill the flash memory settings on my camera. I'll get inside. I use 100,200 or 400 speed?