What contributes more to yield, veg time or full flowering cycle?

What do you think contributes more to the highest yield, veg time or full flowering time? Anybody have experience with this?

I'm about to start a crop that I need finished in October. My strain takes 8.5 weeks. Looking for some advice.

If yield is of primary importance and you had to choose between vegging 2-week-old rooted clones for only one week, but taking the crop a week early OR not vegging at all, going straight to flowering, but letting the harvest run it's full length...which would you choose?

I have a hydro set-up, 1000 watt HPS, in rockwool, growing OG Kush that I always top around week 2 of flower to get several colas.

I'd top them before you switch them to 12/12 and start asap. Most plants I've grown pack on some serious weight during the last two weeks of flowering.

Thanks Satch! Why do you top before switching to 12/12?