you should use whatever provides the most DLI the plants can handle -- if you want to maximize growth.
100w and very likely not an efficient light producer, so maybe 30watts per sq ft will do it with that light on a 18/6 light cycle. So, depending on hanging distance and the area you are covering.. if it's 4sq ft, you want the full thing on for 18h. .. observe and react to plant growth. The resulting length of stem that develops over time between 2 internodes is your guide. too tight = need less. too long= need more.
the effects of red and blue are real and measurable against a control group, however, these effects are fairly small effects. Total light applied is by far more important. Read up on Daily Light Integral (DLI) on wiki is fine.. lots of decent sources for that one... the gist is fine, you don't need to memorize the math.. but puts applying light to a plant in proper perspective.. i.e. it is about photons received per day.. not too little and not too much - the whole observing the internode development above helps fine-tune this.
hours of operation are 1:1 related to resulting DLI, all other factors remaining the same. Increasing rate of photon/s applied is 1:1 directly related to resulting DLI, all other factors remaining the same. e.g. going from 18h to 16 h, while at same power and hanging distance drops DLI 1/9th. As long as you give enough light to avoid flower, this is a valid option to impact how much light you give per day... just as effective as a dimmer knob or using veg or bloom switch on its own etc.
sso the answer is it depends... if not trying to maximize growth between now and moving it outside, i'd just give it enough so that the plant doesn't stretch too much.. obsererve and react.
