Dont put the fans on with the light timer, especially in flower! You will have an insane build up of RH in your room. Leave them on 24/7...the key to a good grow is not just good lighting and a feed schedule, one of the most importantist things is your air circulation.
Deejay
Relative humidity bro, if theres no air circulation then it will rise to an insane amound like 80% and that will cause mold. You want to keep it around 35-50% and yeh thats fine with the fans blowing on the plants. It will make stems stronger to hold those big mo fuckin colas your gonna have!!
Keep your exhaust/intake on 24/7 in flower. Like deejay says it stops humidity(RH) building up. It will also stop mold/mildew from having a chance later in in flower.. Your circulation fan is ok to go on light timer.