I hear about terpenes all the time and didn't really get it until I grew 50 Shades of Grape by Mephisto. That plant is so intensely sweet and fruity, it made me crave bubble gum and I couldn't stop smelling it. Another one that's probably really good is Double Grape (same breeder). I just started that grow so don't guarantee anything. But check out what's possible - one grower reported over 35%THC!
https://www.autoflower.org/threads/31-thc-double-grape-test-result-picture.82567/
As far as keeping plants within your grow space, you just have to plan. I'm too eager to train so I never seem to have issues with height but my yield suffers because my plants don't use enough of the vertical space. Long buds need long branches too, is what I'm learning.
If you keep like with like (stick to indica or sativa dominant for a grow) that will be easier. Allocate extra lateral space for sativa-dominant plants so that you'll have room to pull tops down and out to keep them level and low.
If you wait too long to bend branches over and are worried about breakage, you can wrap them well with athletic tape in preparation, bend them carefully and tie them into place. I do that all the time without problems.
I've only been growing for almost a year, so I'm still learning. But there's a lot of good information on this site.
