Although genetics do play a factor, height has to do with how the plant is grown (how big the container is, amount of light, nutrients, etc), not so much indica or sativa. Sativas will generally be taller, but they are less dense as indicas. Just because a plant is taller doesn't mean it will yield more than another plant. Anyway, I'd focus on quality not quantity.
Autoflowering is good if you need to grow out of season or need smaller plants; however, your yield will suffer compared to what you can get with regular seeds during the regular season.
