Keep up the defoliation and watch the buds swell up from top to bottom.
I've seen some rather large plants under the CXA 3590 COB, I'm actually looking into those.
Ceramic Metal Halide lamps do look great, some come with the option to boost the 315W to 380W. The only problem is, they don't produce enough light to compare with a 400W.
This is a problem with PPFD, I read an article that outlines the difference between HID and LED and PPFD was explained. Plants will benefit more from a higher PPFD than a higher CRI.
I've searched for CMH ops and HPS ops to compare, CMH makes a great supplemental light but I wouldn't use it for a main light.
I've read advertisements saying it can replace a 600W HID, and every grow I've seen has yet to pull a pound from one light.
@TheStickMan pulled a pound from a single 400W HPS, I've seen 600W do much more than that.
Do what you want, experiment and have fun doing it.. just don't believe the hype.