My advice would be to prime a couple leaves off the very bottom, the ones with the most yellow color to them, put them where you plan on color curing and just see how it goes. If it works just do the same thing as the rest of the leaves get to the same color. If it totally fails and won't color cure, wait until the next lowest leaves are a good bit more yellow and see how that goes. If that still fails, leave everything on the plant until it gets cold enough you have to cut the whole plant down and see how they cure left on the stalk.
From the looks of it the bottom 2 or 3 leaves might be ready to color cure if you have the right humidity and heat. You kind of have to sacrifice a couple leaves to experiment and see what works for you.
I've heard somewhere that most plants are mature 2 to 3 weeks after topping the plant and your plant could absolutely be topped right now. So you could give it a couple weeks and then try the method above. See what happens.
