So, Chrissy... you're saying a 5-footer won't yield more bud than a 2 footer?
I completely disagree with that statement.
All I'm saying is... I've been growing canna for nearly 20 years, and I've never seen a 2 footer that out-yielded the 5 foot tree standing next to it.
He's going to have them under a 1000W hps... insufficient lighting won't be a problem.

So, let me rephrase.
*IF* you grow your plants under sufficient lighting for lush, thick growth and *IF* your plants ROOTS are in pots that are of sufficient size to allow big luxurious ROOT systems and *IF* the environment, and nutrients are optimal, then yes. The taller plants SHOULD yield more weight than the shorter plant.