ahh, the 15/9 schedule I do solely because I like to stick some clones outside, and if I don't have them on a relatively short day (for vege that is) they flower as soon as I stick them outside (like in june)
So the 15/9 is just so they don't freak out when they go outside.
if you are looking to just save money on electricity usage, there are some members that do that here, but it's a different schedule, I think they break upthe night with an hour of light... something like that..
I don't really have many indicas, most of my strains are sativa dom hybrids.
right now I have only one indica, and that's the elephant tranquilizer from Bodhi seeds... got me some nice lookin leaves on that strain AND I got a squatty-ass male too, gonna use that for some pollen chuckin
but yea, if you do mess with your light schedule, do it slowly, some strains I've seen flower at 17 hrs of light!