18/6 vs 24/0, is an old, old argument that will always be brought up ... me ?, I use 18/6 ... now, regarding lighting hours during flowering, I found this theory by DJ Short very provocative :

Breeding tips | Cannabis Culture Magazine

you may scroll down to the 'inducing sativa' section, but you'll gain a lot, by reading the entire article (it's not heavy reading) ... :smokin: