I'm currently doing an experiment on LST vs normal growing on the same autoflowering strain to see about yield increases but yes it seems as if LST (tying the plants over to spread out an even canopy) is making a difference (+30-50%) for me at least.

I've also found that the Fox Farms fertilizers I'm currently using (Grow Big, Big Bloom, Tiger Bloom, Beastie Bloomz) are doing better for me than other products I've tried so you might want to change fertilizers on your next grow to find one that works for your style, the current mix sounds like a lot of room for error having to mix 9 things! I'm also using the Happy Frog soil, but in 1-2 gallon pots because it's a dwarf strain.