Help! starting indoors, what light schedule ?

I just recieved my seeds and I am going to be starting them indoors, then moving them outside, what is the light schedule i should use for indoors ? 15-9? 14-10? 16-8 ?

last year i did 24/7 and they all budded right in may when i put them out! im looking to avoid that problem this year...

18/6 Or 24...i Prefer 18/6